Suggestions for a 9 year old horror fan

I hope this is the right place.

My daughter is 9, in 3rd grade and reading at a 6th grade level. At the end of 1st, she tested at 4th grade for reading and comprehension. This blew my mind. The school put her in a book club that year and the tutor told me she reads with the right inflection and changed voices for each character, she was always spot on when they discussed it after. She was an only child until she was 7 and we spoke to her like a small person, rather than just a child. We read complex stories to her as she grew, we played out ideas and concepts as well as fantasy and imagination.

She loves horror. She was placed in a gifted program this year and the director reached out to let me know where she was in reading and recommended I let her read Coraline. I told her she read Coraline when she was 5 and has reread it several times. I've given her a lot of his books he wrote for children, she inhaled every one of them.

I took her to the library and the girl there brought a stack of horror themed books for 5th and 6th graders and she chose 19 of them. That was 3 weeks ago and she only has 4 left. But here is the trouble I'm running into. She can read way above her age but she's still a little girl. I asked her to give me the synopsis of one she recently finished and it went like this:

“These two friends have an art teacher who was murdered and they found out she was having an affair with the chemistry teacher! (I asked her to tell me what she thinks an affair is) It's like how you and dad belong to each other but then he starts taking naps and kissing another girl, that's an affair. Also, I want to ask, what is pot?”

Holy crap. That's a LOT for a 9 year old. I asked to drive in silence for a few minutes while I collected my thoughts, and I kicked myself for not thinking about this when I blindly took her in for older kid books. The murder didn't bother me, or her dad. But affairs and drug use, sexual content – that's a hard stop for us. I wasn't a gifted kid, I was free range and my aunt had me watching movies with her (11 years older) about teenagers doing teenager things in the 80s and my innocence was gone way too early. Sexual content doesn't need to be in the mind of my 9 year old.

The back of the books dont tell me this stuff in detail. I tried to find an app where you can scan the ISBN and get a review with bold words explaining its themes, and I found one for Apple. It's called Book Scout, and it sounds amazing but I have an android. I'm open to suggestions here also.

I posted this in a local mom group and I got hit with a lot of attacks on my parenting. And I get that, I didn't do a good enough job vetting this stuff. This is all new to me, but I'm not going to spend a lot of time kicking myself over whats done. I'm going to keep giving her books that challenge her safely but how to navigate doing that is really troubling me. Books will never be banned in my house, but staying mental age appropriate while keeping up with her reading level has my spinning my wheels.

Outside of parenting critique, can anyone offer anything helpful, or recommend books that will stay in her wheelhouse while keeping to her maturity level?