Need advice on combatting the socialization argument for radical grade acceleration!!

As I mentioned in my earlier post, we went ahead and gave our soon to be 5 year old a second achievement test (the first was 6 months ago)- we gave him the WIAT II - (the psychologist's suggestion)
The test results more than supported our intuition that our child needs to be in at least second grade to be academically challenged.
We feel comfortable making most all arguments accept the social ones although he is a social animal and is comfortable in most all social situations.

We hear so much about bullying. Is this a real concern?
Our son has been playing on the chess circuit for the past 6 months and spends lots of time with older children. They are all so respectful and kind to him. Is this just chess kids? Am I naive on this one?

Has anyone had their child accelerated academically but taken out of the classroom when doing sports, music, etc with other children?

What are some practical ways to address the handwriting issue? Has anyone successfully convinced the school to let the child type?