There are many very simple truths that can be applied here.
If he is truly exceptional (ie. a prodigy) he WOULD be flagged for scholarships and you would have been approached. Child prodigies in early high school years are not simply working 'at the top of their classes', but at massively massively advanced levels outwith curriculum that high schools provide (state or private).
Very very clever children (which I think would be a fairer assumption), do fantastically in a range of educational environments, including states schools, if encouraged, enabled and supported.
Very very clever children often burn out in their early adulthood. The pressure (even if you don't intend to put pressure on him, you ARE, by taking this attitude at all) high achieving children are put under often lots of different pressures just by the adults around them valuing their intelligence highly in an open manner. Gifted child burnout in late high school, college/uni or early adulthood is INCREDIBLY common - they can find that without the expectations of others that they are meeting to please people, that they have simply run out of motivation. They rarely learn to study properly unless actively taught, because they take everything in like a sponge and test fantastically with little to no study. They read books like most of us drink water and they become completely used to (and expectant of) the constant praise and pride of being and doing 'better' than peers.
Let him be a child, facilitate any interests he has that you can, listen to him chat about what he's fascinated with and let him excel if he excels. I was your son (though a daughter), 18 years ago. I burned out, became completely riddled with the anxiety of not living up to expectations and didn't pursue further education due to my mental health - despite on paper being, yes, 'remarkable'.
It's not that rare, he is unlikely to be the next Einstein, and if he's going to be - he will find a way regardless.
There is a lot of literature on gifted-child burnout, I'd suggest having a read and calming down a little bit. (Though I've no idea why anyone would suggest you shouldn't burst with pride and other very normal reactions to your own child's achievements!)