He's big enough now you're not going to hurt him and he knows it. Two choices: 1: he learns how hard it is to dig ditches and shovel gravel because that's where he'll end up without an education. 2: reward based compliance; there's something he desperately wants and you can cut a deal with him to earn it.
I'd also recommend gathering some of his hair from his brush and sending it off for a drug test. It's not what you want to hear but it is something you need to know. You could get lucky and just have a hormonally unbalanced defiant kid.
