My sister actually left school at 15 and went to college. She didn’t do early graduation. She just left and went to college but she also had a perfect SAT at age 12, so there are cases where an early out makes sense. The OP may want to look at some of the programs that allow students to start college, without officially graduating, and going in as a high school senior. I know, for example that USC has one as well as Simon’s Rock
http://dornsife.usc.edu/resident-honors-program/
http://simons-rock.edu/
This is one list, there might be others - http://cty.jhu.edu/imagine/resources/college_entrance.html
These programs are made for students who need to move on, for academic and social reasons, but who have not finished high school. You don’t need to graduate and they are meant specifically for students who are ready for college level work, but they are not traditional college programs. For some, you would apply during Jr year, so the timing is good. You won’t get a HS diploma, but you would be able to get a college degree.
Many many years ago my own sister, who was only 15, left high school, at her counselor’s recommendation and my parent’s blessing, and attended a very very small state school where she was much happier. She later transferred to the state flagship, when she was older. For some kids there is reason to move on. The OP won’t be competitive for traditional elite colleges at this point. But he could be ready for an early start program if he really wants out.
Do a google search for early college entrance programs. There are many, but you have to look for them.