My son will turn 7 in July and is completing 2nd grade, having started KG at 4. He scored high enough on the SCAT to qualify for the CTY programs in math and language arts. He gets weekly homework, which he does after some prodding (the work is not difficult), but he never turns it in on time. It's up to him to give the teacher his folder, but he is too busy playing. In general he seems to regard school as a social experience. His teacher says he is advanced in reading and math but rarely puts forth his best work.
On this forum and in books about gifted children, especially boys, who refuse to comply with their teachers because they are not learning anything. In his case I think it's a matter of prioritizing fun over school work. I am not worried about his falling behind academically but about his developing bad habits that will hurt him when grades start to count. He is a voracious reader at home.
I guess the general question is whether we should really be after him to take his schoolwork more seriously or just let time pass and hope he grows up. Many boys his age are in KG. My wife was a serious student in school from the beginning, whereas I "woke up" around the 7th grade. I am more in the "wait and see" camp than she is. I don't want too much scolding at home to distract him from the informal (but real) learning he does.