Sounds like my 15 year old a bit.
Great at making money, no need for work a paper round or anything, just buying and selling his mates things. No idea what he wants to do, I've even offered to buy some ladders and rent them to him until they're paid off to start doing the neighbours windows. I've suggested trades, fucking hell everything, everywhere we go I point out the kinds of careers there are.
Last week we went looking at colleges where he might do A levels. I feel like you, the workload will surprise him but I'm prepared to let him have the opportunity I was denied (I felt quite jealous looking round the places tbh). I think he fancies the idea of going to uni and going out every night and I see it as the thing that'll make him leave home. He won't get EMA at college but I'm happy to pay him the same amount. If you're on low wages your lad would get it, £30 a week if the household income is less than £30k.
Worth mentioning A levels aren't the only way into Uni and he can do something else after the first year, or sooner if things don't work out.
I work with 16-21 year olds and see the kind of shit you end up on if you get lumped in the 'needs confidence building' category. It's like going from school to The League of Gentlemen jobclub. If you really think he confidence boosting though, how about Prince's Trust? They do 13 week courses with a residential. I've known some kids do really well on them.
I think the important thing is to let him make the choice and support him in that, even if something you feel won't work, just be there to pick up the pieces.
Oh and he won't get dole until he's 18, unless he's estranged.
And please stop doing his homework.
