Books for a 9yo boy at a 7th grade lvl.

So I recently tested my 9 year old as a homeschool requirement and he is at a 7th grade reading level. I am trying to find him books that will challenge his reading skills, but some of the topics at that level are a little intense. I'm trying to find something that will match his interests which are still pretty immature, but that isn't too easy.

Edit: Definitely nothing spooky. He is into science related stuff, but spooky is all the way off the table. He gets scared very easily.