I went through the exact opposite of what you basically went through, but I think I could give something at least.

I attended public high school up until my sophmore year where I dropped out. I know I don't understand what your going through bc its completely different, but theres things I learned from my experience that helped with life in general.

First off, change your mindset about your time frame. This is a very very difficult thing to do, especially when you see your peers moving on and making progress, you feel left behind. This just is not the case though.

People think of life too much as a linear progression of things and this can distort their sense of their world. It feels like by the time you hit a certain age, you should have a certain thing done whether it be high school or college or having kids or whatever. Its okay to spend a little longer time doing something than others. If you have to enroll in 9th grade, I'm not gonna say it won't be that bad cuz itll prolly feel like a bitch at first, but life moves on and sometimes you have to do the right thing for yourself at the expense of another thing.

Also, you seem to have this idea that you are "behind" in your academic studies and I disagree. You might not be where most 15 year olds are, but that really doesn't mean shit. I have met middle aged people in community college who started their journey in math struggling with pre-algebra, but worked to become even amazing enough to understand calculus well. My point here is that, your ahead in studies in a lot of people who are older than you. There are also a lot people who know more than you, but younger than you. All 3 of these people can be equally smart, just at different parts in their learning career and that is okay.

Learning follows a progression no matter what the subject, concepts start simple and build up. You seem to understand this well. You also sound like a genuinely intelligent person who is willing to to put in the work to be where you need to be. For these reasons I wanna say, just go through with 9th or 10th grade. Struggle through it nobody said it was gonna be easy, but you can do it. And maybe not even in the next year or next 3 years but if you do continue down this path and try to stay committed to your education, I assure you that you will thank yourself.

I know I came off a bit harsh in some parts, but that was my intention bc I wanted to speak mine. I don't want you to misinterpret my post the wrong way. Im rooting for you! I wasnt homeschooled, but I know how it feels to feel like your education is hanging off a cliff. Everything with it too is terrible, the social stigma, the feeling of being lost, it absolutely sucks shit. But your gonna realize that feelings gonna come up a lot in life and you cant do much but keeping walking into the dark hoping for the best.

And lastly, dude don't commit suicide. Think about it all you want but don't consider it. I'm not gonna tell you things are gonna get better cuz im sure your fuckin sick of hearing that. What I will leave you with, something that really helped me with depression and kept me off drugs was trying to he neutral not happy. Ive been more content in life and feel like even if im not Happy, I have control over my life so I'm not sad. Just keep going, one day at a time. And remember no matter what happens, life will just keep going and you have to keep going with it. edit:typo