I'm glad you are going to meet with the principal. That is a great place to start. I hope they are helpful. From your description, cyberschooling isn't an option I'd put very high on the list. If he's really social he needs to be with other kids IRL not just on the computer.
If it looks like school isn't going to pan out for first grade, the one thing I would suggest is to try to organize some homeschooling activities where you might attract some more academic kids. Advertise them widely and see if you can pull in some other kids. I would suggest picking areas your son is interested in that tend to attract geekier/smarter kids. One idea:
http://www.flrobotics.org/ A science fair is another idea. You could teach the co-op or lead the activity or find another instructor. Also, you might look outside of homeschooling to activities with other kids too. We've had luck with mixed age groups with programs at the library, science center, etc.