M.W.
I am a psychologist who's been homeschooling for 8 years. I do not have a child with autism, but I have a friend who's homeschooled her autistic child for many years. For her, homeschooling was a matter of necessity. Her son simply couldn't cope with the school environment. If your son is doing well in preschool, he may do well in school.
You obviously are a concerned and involved parent and whatever you decide to do, now or in the future, will be in your son's best interests. Do remember that homeschooling isn't a one-time opportunity. If he goes to school and it isn't working, you can homeschool and vice versa.
I will say that much of what has been written here is just patently false about homeschooling. The research (and not just parents' claims) clearly shows that homeschoolers outscore their public schooled peers academically. They also have the highest self-esteem of any group. As far as social skills, what skills are we discussing? The ability to follow the crowd and backtalk the teacher? What about completely disrespecting parents? These are social skills I hope my children fail to master. If we are going to use specific instances of failure to impugn homeschooling, let us use the same standards with public and even private schools. Despite more money being put into education, achievement continues to decline.
A homeschooler wrote recently to say that if as products of a public school system we are not qualified to teach our children the most elementary of subjects, why on earth should we educate our children via the public school system? So they can be similarly unqualified? As for the woman who hated being homeschooled, I wonder if you would have fared any better in a public school? I agree with Oliver DeMille that all education is self-education. If you weren't motivated to learn at home, you probably wouldn't have learned anywhere.