Heavy story, and i'm unhappy to read that you are still in an abusive situation.
You say your in ninth grade. How old does that make you? I'm from the netherlands, so I don't now about the grade system

You come across as an intelligent kid. I understand your cutting, but I think we also both know that in the end that's not the sollution to your problems

is there anyone you can talk to? A teacher perhaps?
I don't know much about bullying, but do know a lot about being abused in any way (

) so I would like to say to you: hang in there! At least until you are old enough and/or have the opportunity to get away from your abusers. And I do mean get away alive. The other option... well, look at it this way: staying alive, getting away and making a good life for yourself is the ultimate revenge.
I'm glad you found your way to this forum. As you can read you are not on your own, other people (have) suffer(ed) the things you suffer, so at least here you have a place to talk to people and perhaps find the strenght you need.
Anyways, my crummy way of saying: hang in there, try to take care of yourself. and if you want to get anything of your mind, just write it down here