A Stanford study of men’s basketball players who extended their sleep to 10 hours a night found several positive outcomes. The players ran faster in both half-court and full-court sprints. Their shooting improved by at least 9% for both free throws and three-point shots. The athletes also reported improved physical and mental well-being.

Mah, C. D., Mah, K. E., Kezirian, E. J., & Dement, W. C. (2011). The effects of sleep extension on the athletic performance of collegiate basketball players. Sleep, 34(7), 943–950.

https://doi.org/10.5665/SLEEP.1132

The American Academy of Pediatrics recommends at least 9-12 hours of sleep for children ages 

6-12.

https://publications.aap.org/aapnews/news/6630

In a study of male team-sport athletes who were sleep-deprived, average and total sprint times decreased.

Skein, M., Duffield, R., Edge, J., Short, M., & Mundel, T. (2011). Intermittent-Sprint Performance and Muscle Glycogen after 30 h of Sleep Deprivation. Medicine & Science in Sports & Exercise, 43(7), 1301–1311.

https://doi.org/10.1249/mss.0b013e31820abc5a

"Overall, better quality, longer duration, and greater consistency of sleep correlated with better grades. However, there was no relation between sleep measures on the single night before a test and test performance; instead, sleep duration and quality for the month and the week before a test correlated with better grades."

https://www.nature.com/articles/s41539-019-0055-z#:~:text=Sleep%20measures%20accounted%20for%20nearly,better%20academic%20performance%20in%20college.