I guess we're lucky that both DC are early risers.
It sounds a bit infantile, but advise should his behaviour continue, you will be making a chart like you would do for younger children, subsequently he'll be treated like a younger child with earlier bed time, plus other sanctions.
Advise if he wants to be treated like the young man he is, then his behaviour needs to reflect that. One sanction could be, if you drop him at school, you'll do so as close to school as possible and treat him like a young child going to school.
At this age they're a mess of hormones, with that I think they revert to the stage of testing boundaries, so you really need to follow up on 'actions have consequences.' Hopefully the threat Alone of the school example will have him being more compliant.
I don't know what jobs you have around the house, possible add on further chores if he continues to misbehave. You've done a great job showing him that if he behaves he'll get rewarded. Hopefully it'll sink in deep and this phase should pass. I definitely think he's seeing how far he can push you, he's found out that you won't tolerate it, so whilst it feels like Groundhog Day, hopefully the cogs are turning and he'll treat you with the respect you deserve.
I know it's a work night but 
from me to you. I'll get thinking of possible punishments. It could be nerves, like avoidance, as soon as he's there he'll realise it isn't half bad, an exciting new chapter has begun for all of you.