Alternative anime to Demon Slayer suitable for 9 year old?

Avatar:the last Airbender

And then follow up with Legend of Korra!

Maybe look into "little witch academia"

@Pillagenplunder@lemmy.world has the go-to suggestion: you can't go wrong with giving Avatar: The Last Airbender a shot. I don't know if I'd say it has similar themes or notes to Demon Slayer but it is an absolute winner.

I also highly recommend the movie Spirited Away if you haven't watched it together yet. It's got some similar themes and notes more suitable for the whole family. Instead of stopping demons with violence, Spirited Away finds diplomatic ways to deal with spirits. Also just a masterpiece of a movie.

I'm having trouble thinking of similar anime series for a younger audience but there are some other anime-inspired (like Avatar: TLA) cartoons that deal in similar themes. Steven Universe follows a group of heroes that stop corrupted gem creatures in hopes of curing them. And Star Vs. The Forces of Evil is about a Sailor Moon-like princess from a magic realm that travels to Earth and fights the forces of evil with her best friend trained in karate.

As someone who has watched anime for decades, I personally do not recommend letting anyone under high school age (and even then...) watch any anime that you have not fully watched and vetted yourself. Anime is notorious for pulling a fast one on the audience and doing a sudden genre/maturity shift (from Narutaru which looks like a cute Digimon-type monster battle show but involves a lot of murder and rape, to School Days which looks like a standard high-school romantic drama but ends with the protagonist's head in a duffle bag). These "gotcha!" moments are part of what makes anime unique and fun, however it also makes vetting anime really difficult for guardians. And that's just in terms of violence; anime often feature (what I consider) really unhealthy portrayals of romantic relationships, female sexualization, and sexual harassment in general (the latter of which often is played off as a harmless joke). Even "kids" anime like Naruto, DBZ, etc can be surprisingly mature. You have to pay very close attention to the show's rating, but even that is highly subjective and can change from season to season or even episode to episode, and often doesn't include factors like "does this series promote toxic relationships?" that are important but often overlooked when vetting media for such a developmentally-vulnerable age.

There definitely are anime out there that are appropriate for younger audiences, but your daughter might find them boring and dated by comparison (anime fandom nowadays is all about watching the latest hot series, not digging years or decades into back catalogues for shows that have completed and thus easy to confirm are age-appropriate to the end). Generally, slice-of-life CAN be wholesome (eg Non Non Biyori or The Flying Witch) but your daughter may find them boring. There are also more appropriate action series out there, but you gotta find the stuff that's aimed for really young kids like Digimon. Magical girl anime is also an option (some ancient examples: Sailor Moon, Saint Tail, Kamikaze Kaitou Jeanne), but that's a popular "gotcha" genre so you have to be VERY careful.

In summary, having a kid who's interested in anime means either having to very carefully vet each title yourself and praying your kid doesn't gain an independent streak and start exploring titles herself, or giving up and hoping she doesn't stumble across the animated equivalent to 80s/90s kids stumbling across beheading videos and scat porn in the early days of the Internet. Good luck?

Even kids stuff can be a bit risque due to different cultures. Digimon has a scene where the kids are picked up by a random college kid, Yu-Gi-Oh has a scene where Tea is implied to be about to be sexually assaulted and the OG dragon ball is half about a girl who wants to get laid and an old pervert who also wants to get laid.

Do you know what about it interests her? Is it the action or the pretty art? Both those could pull different threads
- Sailor Moon is another great example: despite being a kids show it underwent a LOT of censorship changes when it was aired in the US (although much of it was LGBTQ erasure). American media has a lot of issues, but I'd consider US-made cartoons significantly less likely to contain problematic content (especially anything from the last decade, as US studios have become more focused on avoiding that sort of thing because of public outcry, whereas I don't get the impression the Japanese public cares as much).
Whelp, I guess I can mark School Days off my watch list.....

My 8 year old has been watching Demon Slayer and loving it. But she had a "gateway show" to get into that -- InuYasha. She saw me watching InuYasha and started watching it with me and then became addicted to that. I think that set the bar for what kind of anime she likes, , and so watching Demon Slayer seemed like some kind of natural progression. Anyway, it really depends on the kid, but if they can watch cartoon violence and not get freaked out, then it should be fine.

My Hero Academia is also violent, but it's a bit less graphic than Demon Slayer, and it's themed around super heroes/villains so the concept may be more approachable for a child. It's one of my personal favorites, but fair warning: The themes do get somewhat more mature as the show goes on.

If your kid has an interest in science, Dr. Stone could be a great fit. Contains some violence, but it's mostly about a super genius recreating modern technology using primitive resources after an apocalypse.

Another one in the science vein, Cells at Work tells the story of anthropomorphic cells living and doing their jobs in a human body. Again, some violence, but it's mostly cartoonish and shouldn't be much of a worry for a kid.

Fairy Tail is also a good choice, especially since its audience skews younger than the other recs I've given here. It follows a group of wizards at a famous guild as they take on quests and go on adventures. Very kid-friendly with a huge backlog of episodes.

On second thought, maybe give Fairy Tail a miss due to the fanservice. I apparently blocked all those scenes from my memory when watching as a kid.

Hero academia: actually does become pretty graphic as series goes on Dr.stone: good pick Cells at work: safe too but not in the genre as demon slayer Fairy tail: not kid friendly at all because of all the ecchi
- Oh damn, you're definitely right about Fairy Tail. It's been so long since I've watched it I completely forgot about all the fanservice. It's bizarre though, because if it wasn't for that it'd fit right in with other "Saturday morning" kids anime like Yu-Gi-Oh and Pokemon
I've only read the manga, but I found Dr Stone to be really misogynistic, in a low-key but pervasive way. Nearly all the female characters (especially in the first half) are vapid and highly sexualized. Maybe the anime is better? MHA's female characters are also overly sexualized, but at least they're as well-developed as the male characters.

Also to be clear, Cells at Work: Code Black is a spin-off which is NOT age appropriate (albeit the superior series IMO).
- Nearly all the female characters (especially in the first half) are vapid and highly sexualized
  
  You're joking, right? Sure, some female antagonist characters are like that, but Yuzuriha is an essential member of the party portrayed as hyper-skilled, Kohaku is super strong, smart and doesn't fawn over the protagonist despite clearly having feelings for him, Suika is literally just a silly kid, etc. Just because they're using relatively revealing clothes (which aren't even that revealing, mind you) doesn't make them highly sexualized.

Could try Spy x Family. Still action, but less explicit in its depictions of violence (though there is still violence), and overall wholesome story / message.

I’d give Natsume’s Book of Friends a look. it’s a good middle ground between Pokémon and Demon Slayer. It focuses on japanese folk lore monsters and what nots. there’s no major violence or killing.

Natsume is a pretty good suggestion. There are some episodes that can have sad themes, but not any worse than you find in Disney movies aimed at kids. Also, there is a lot of content so you can just turn it on and let it play for a while to keep them busy. Finally, it is an anthology, so episodes are self-contained stories for the most part, so if they get distracted and miss the plot of an episode, its not really an issue.

Bofuri is surprisingly good! Not in any way serious in tone, since it all takes place in an MMORPG, but some good action scenes, especially in the first season.

Pretty sure it's completely kid friendly (no fan service or other anime weirdness.)

I'm going to second this. The fights are still pretty action packed + there's a derpy looking flying turtle.

Spy x Family

A Silent Voice - has some serious/mature themes but someone your daughter's age can understand

Bocchi the Rock

I think Bocchi is a good recommendation, especially if the kid has social anxiety themselves. Though since one of the supporting characters is an alcoholic, I think parents should consider the maturity of the child and decide if they think some background explanation is needed.
- K-On! would be a way better choice...

Any Studio Ghibli movie seems to be age appropriate and has a female protagonist featured in most: Princess Mononoke, Kiki's Delivery Service, Howl's Moving Castle, Totoro, Spirited Away, Ponyo

I get what you’re trying to say but to be fair Mononoke opens with Ashitaka shooting off a dudes arms with an arrow.
- I'm not gunna lie, haven't seen the movie in a long time so I completely forgot about all the maiming in the film lmao good catch
Yeah.... Graves of the fireflies

It's old by now but I'll chime in with Cardcaptor Sakura.. I enjoyed that as a kid at a similar age.

Maybe oldschool Dragon Balls or Rurouni Kenshin? I wonder if Hunter x Hunter or One Piece might be better? I've only watched the former a bit and I think it has significantly less graphic violence at least. Alternatively maybe something completely silly like Samurai Pizza Cats.

In one Hunter x Hunter episode, a guy bites off another guy's head, sucks out the skull, and spits it as a projectile at another character, for a quick two-fer kill. Real kid-friendly stuff.
Eh, Hunter×Hunter gets quite heavy. The Hunter Exam arc gives a slightly lighthearted impression compared to latter parts, even if it does not have a ton of explicit gore, it is violent.
- The series is sorta violent even before Chimera Ants, where the evil-ness is kicked up to kitten-kicking, puppy-eating, "Sauron and Voldemort would hold a villain intervention because it's too edgy", gorey mess. Before that it was still relatively edgy shōnen but it seemed to take a slight turn there.
Ruroni Kenshin is a pretty dark historical war story when it gets going fully, I really don't think a child should watch that. The beginning is intentionally deceptive for narrative reasons. The newer one is a lot more upfront with it.

Dragon Ball is extremely inappropriate, If I were in that position I would not want my daughter to watch that and mimick ANY of the behavior Bulma commits. Especially with Roshi. The super fanservicey stuff gets cut off around Z or slightly before, but OG will shock you if you haven't read or watched it in a while.

For my pick, it's hard to list anything super similar minus what was already mentioned. As a cool anime for female empowerment I'd pick Bocchi the Rock, anime about a girl overcoming social anxiety to fulfill her dream of becoming a rock star. All female cast pretty much, no fanservice, pure comedy, good story, and rockin music. There's like one or two inappropriate jokes that'll fly over a kid's head, but most children shows in America had worse.
- The Kenshin animated series skips most of the hyperviolent stuff and starts after the war. You could start with that show, and watch the OVA later when they are more mature.
  
  Agreed on OG Dragonball. My son showed interest in DBZ, and I thought it might be good to go back and rewatch the series to get caught up. I started my own rewatch and was shocked at how sexualized it all was, especially given the ages of the characters. And it's not even like side-plot fan service you can skip. Bulma, a minor, is flashing people left and right to get what she wants, including obtaining Dragonballs.
- "NO BALLS! NO BALLS!"

IMO Demon Slayer is one of the more kid friendly animes out there (of its genre).

If you dislike the gorey scenes like decapitations, but are fine with only blood, Saint Seiya is a great classic – five boys fight to protect the goddess Athena from the forces of evil. From memory, there are no scenes of dismemberment, and sexual fanservice is pretty much nonexistent. Lots of magic blood flowing out of bruises, though.
Saint Seiya Omega is a newer, even more kid friendly sequel. There's still some blood, but it's definitely muted in comparison.