No one can answer those questions but you. If you decide to homeschool and it doesn't work out, can you return to that school? If so, then you don't have much to lose in trying out HSing. If you have 2days of school available while you HS that would be great. It's a place for him to make friends to schedule other playdates/activities with. Have you checked into HS groups in your area?
If he's in 2nd grade math now, why would they want to make him repeat it? He can learn reasoning skills doing 3rd grade math if he's mastering 2nd grade math. I would likely push for 3rd grade w/ the option being if that doesn't work out, he drops down to 2nd grade math.
