In the traditional sense, it'd be hard to tell whether he's upper class or not. From the way he presents himself, he almost certainly attends a public school, but these days the majority of people at public school aren't upper class by lineage. His parents are certainly wealthy, and I'd imagine that a considerable portion of his success is due to being well funded (my parents certainly wouldn't have bought me an iPhone or macbook at the age of 12) and well supported at home.
Fundamentally, I'm sure the guy is of above average intelligence. He has very good support from home, and actually has funding for his startup. However, apart from his age there's little differentiating this from other iPhone app based startups, and I would be surprised if he manages to maintain the level of progress he's had recently once life starts to be complicated. If his life is anything like mine was at 16, school is completely unchallenging and he'll have oodles of free time. That doesn't last forever!