Hanging In,
Sounds a lot like my 11 year old who carries a diagnosis of adhd (combined) and depression. He's quite smart but has this defiance issue wtih classwork if he just doesn't feel like doing it. It is extremely challenging.
What we have done in school is make sure that his recess is not taken away for not completing schoolwork and making sure that classwork not completed is sent home to do for homework. That has helped since he doesn't want to spend more time that he has to on homework.
He's not diagnosis'd with odd at this point, but does have some symptoms. However, he is much different at home than he is at school. I believe there is some school anxiety there as well.
Socially, he's like your son. He has a couple friends at school, but is, by no means, part of the pack.
I highly recommend Ross Green's book as well.
Glad you have found your way here.
Sharon