Adele Brodkin: The good news is that he is able to focus, sit still and do very well in small groups and one on one. And that is really good news; it bodes well for his academic future, as you know. The not so good news, though, is that he is not making "many friends". Succeeding socially is as significant a predictor of school success as is focusing and following directions. But the key word there is "many". He really doesn't need a lot of friends. As long as he has one or two pals, I would be less concerned about the quantity. I suggest that you support those friendships that he has made as long as you think they are mutually beneficial. You might also suggest to his parents that play dates be arranged with at least one of those children outside of school. Now and then, you might bring another child to join him and a friend in some project, which could be a way of broadening his social horizons.
I can only guess about some possible reasons for his distractibility in circle time situations or his lack of understanding about physical boundaries. Is this the first time he has been with a large group of children? Is his home very staid and quiet? Or, on the other hand, is there too much stimulation and physical confusion at home? Clearly, you can't ask such questions directly, but if you get to know and befriend at least one of his parents, the answers to such questions may become apparent. But whatever goes on at home, you can continue to reinforce your expectations about boundaries in school, particularly with praise when his behavior is appropriate. You are clearly very tuned into children's social-emotional development which suggests this boy and his classmates will have a very good year learning the most important lessons of kindergarten.
For more advice by Adele, check out the Between Teacher and Parent column.