Which sport should you encourage your child to adopt? My guess would be cross-country running, swimming and rowing, which have all the important characteristic of encouraging perseverance and long-term planning. They also make your child hang out with the "right people" as these athletes feature prominently among the best students. But these are just my impressions, let us see what can be done with more than anecdotal data.
Charlotte Cabane and Andrew Clark look at US schools, although not quite at the level of athletic detail I would have wished. Healthy students are more likely to participate in sports and later be successful in life. But those participating in sports are also more likely to be healthier. The direction of the causation is not clear. But of interest here is whether participation is sports is an important determinant in latter outcomes. Using the National Longitudinal Study of Adolescent Health, which looks at students who were in grades 7-12 in 1994-95, they can track how the students are doing as late as 2008. In the end, participating in team sports once a week as a student increases the hourly wage by 1.5%. Not a lot but still significant, especially as this for adults in their thirties, and gaps tend to widen later on. Individual sports seem only to have an impact for adult outcomes of girls.