Don't get me wrong; if there's a closely contested 10-9 match in the 3rd period, I'd rather be coaching a smart kid than a dumb kid. However, I think success on the mat and GPA have very little connection. I was a first team academic all state selection and won my fair share of matches--but I also got beat by some guys that I think had trouble tying their own shoes. Athletic ability, work ethic, and coaching have made champions out of many bad students...even at the college level. Plus, I think mat savvy can exist in a kid that isn't necessarily book smart.
That sixth sense for knowing the clock, the score, and your mat position are not found only in kids with high SAT scores.