I would not dare to directly correlate winnings within sportbetting with the amount of intelligence or the IQ of a person, to be honest.
There are simply too many other factors which the bettor have absolutely no control over and cannot do anything about them.

Though, I would admit, it would take some high level of intelligence for someone to consistently hit the nail on the head several times and pocket and good amount of money, but it would not be an ultimate test whatsoever.

To me, it would take an actual test scientifically proven by universities specialized on the study of intelligence and self-awareness to know how intelligent a person can actually be, this is rather a very random and qualitative way to see intelligence, specially if we keep in mind betting also depends much on luck.