(1) You seem very smart. (2) You write very well. (3) You deserve a great life. I'll bet you can get some good ideas on what to do from your school counselor, a county youth services agency, or a counselor at the local YMCA. If all else fails, talk to your high school principal or vice principal. Good luck!
I do not practice in WA, but I may offer some general advice. You do not say how old you are. You cannot leave your parents' home without permission, unless you are a legal adult or you apply to a court for early emancipation. To be emancipated, you would likely have to prove to a court you could support yourself financially, and it is in your best interest. Of course, if you are close to the legal age of adulthood, you may become an adult before you are emancipated. Emancipation is not always a quick process.
All in all, I agree with the first answer. Speaking with the suggested persons may result in a more practical and immediate solution.
You may be able to file what's called a Child in Need of Supervision (CHINS) petition. Kids and/or parents file CHINS petitions when they believe that the child can't live with the parents, and there is another place that the child can live, but the kid and parents can't agree about it. Since you live in Mt. Vernon, I've attached a link to the Skagit County Superior Court's website about CHINS. It has a lot of information about what exactly that means and links to court forms.
When you file a CHINS petition, you'll be assigned an attorney at no cost to you.
Good luck! Every child deserves a home that is happy and healthy, and especially one that is not abusive.