I'm very sorry about your living situation anxiety, needing to feel safe. I can identify, I feel for you, and I hope it works out for you.

High school seems SO incredibly important when you're deep in it. Like your entire life hinges on what grades you get, that it decides your entire future... It generally doesn't. A lot of what you learn in high school is outdated, wrong, or of no use (not all--some). I can't think of a single person I've met in my decades+ adult life that cared whatsoever what grades I got in high school--lovers, friends, employers, and so forth. Any skills I've needed in my adult life, I've learned as an adult.

If for some reason you can't graduate high school, or do badly, you can always get a GED, take night classes and the like. There are well-known textbook cases of people who never did well in school (ADHD, dyslexia, et al) but turned it around as adults. A good coping mechanism as an adult for having done badly in high school: read, take classes, learn skills, get certificates, take noncredit courses. And keep a record of your accomplishments in this regard--it will come in very handy as you grow older, and this is the kind of stuff that impresses employers, helps you move forward in life. Don't focus on grades and degrees--what's more important are the experiences you have, the stories you can tell, opportunities to expand your mind, have adventures. And I don't know a single adult who's ever stayed at one job, or the same career--it changes a lot when you're an adult, you grow, you develop, you expand, you go in new directions, and this continues for decades.

To answer your titled question: Academically, I did extremely well in school, gifted programs, advanced placement, bored out of my mind, everything came so easy I never had to try. Socially, however, I had a horrible, horrible time.

Also, keep in mind that there are multiple kinds of intelligences: you may not be book smart, per se, but you may be gifted at other intelligences: social, emotional, diplomacy, creative, detailed, and so forth. Learn about the different kinds of intelligences, how different brains work, and try to figure out the best way you learn things. Some learn well reading books, others have to take classes, others listen to audio books, others do well hands on, etc. You can't judge a fish by its ability to climb a tree. You have gifts, and things you struggle with, just like every other human on this planet. It's just a matter of finding the kind of environment you work best in. Which is done thru experience, experiments, trial and error, learning as you go.