Prior to school starting, arrange some play dates with other kids from his school. If he can form some friendships outside of school, it will help him when he goes back to school. Also look for opportunities such as church groups, Little League or Cub Scouts. He might be interested in one of these, and it will give him a chance to connect with classmates in a non-academic environment. This may help him relate better with his peers at school.
As far as moving goes, if he struggles to make friends he will likely take the same challenges with him to a new school. However, if you judge the situation to be unworkable at some point, moving would be worth looking into. Peer relationships are too important to his development. Continually feeling isolated would not be healthy for him.