This is a hard age for parents and kids - they want their independence but they need to learn how to be respectful and responsible in attaining it. If you take away the one thing they look forward to and/or are good at - say hockey - you take away all their motivation and the battle spirals ... finding the right balance can be so hard sometimes.
Credit where credit is due, he gets himself up every morning and off to school which is a 25 minute walk with no busing and is never late. He doesn't hate school - he attends every class - he just enjoys the social component more than the academic component.
My friend was in the same situation once and the teacher told her - school is not worth losing your relationship with your son - some kids need to fail to succeed and while I'm not condoning it, it's the biggest life lesson he may learn so back off, regain your family and let the chips fall where they may.