Not that bad!
I have 2 kids, one 12 year old boy, and a 9 year old daughter. Me and my 12 year old boy watched the 2017 IT in theaters when he was 10 and he handled it perfectly. My daughter was a little scared of this one, but she wasn’t too affected.
Violence: 6/10. This movie has some violence, and it’s much more than the 2017 one, but it’s nothing that kids can’t handle. Pennywise bites a kid’s head. He rips out someone’s hearts and chomps on it, A character slits their wrists in a bathtub. People get cut, stabbed and more. There is a lot of blood and gore, but not much that a kid can’t handle.
Language: 5/10. This movie has cursing in almost every line, but in schools, kids curse a ton everyday, and most likely your child curses in school too, so language isn’t a huge concern.
Sexual content: 2/10. There are a good amount of sexual jokes in this movie, kids and adults will share a laugh in these, but there is a scene where Beverly gets sexually abused, and for no more than 5 seconds in the movie, you can see a naked old lady, but her body is blurry since it’s not focused, and in the background, and there is a naked lady/monster that is grey and has breasts flapping around.
CONCLUSION: Kids are able to watch this movie, but just keep it 9+ in case they might get frightened.