I don't know if you're familiar with this site on early college programs -
http://earlyentrance.org/Home. FL doesn't have one or not one listed on this site.
Simon's Rock at Bard College (
http://simons-rock.edu/) is one of the few early college programs nationally, but that's located in western MA and your son would have to live on campus there. You'd have to feel comfortable that your son could socially/emotionally living on a college campus on his own. Then, there's the tuition, scholarships, financial aid can of worms that you'd have to contend with.
There are a couple of things which you could try out and see what happens. You could contact a local community college or state college/university and see if they'll allow your son to audit a course. You could enroll your son in some (free) online college courses (MOOCs). MIT is now using MOOCs to identify potential candidates (
http://www.csmonitor.com/USA/Society/2014/0223/How-colleges-are-finding-tomorrow-s-prodigies). You could also do what HowlerKarma suggests and work on completing the high school requirements first.
Would Stanford's Online High School (
https://ohs.stanford.edu/) be an option? That's somewhat a gray area between homeschool and public school.
My ds is a bit younger than yours but we're in a similar boat and I do have sympathy for you.