When it comes to the Center for Disease control, they state that the proper amount of sleep can be beneficial for an individual's overall health and well-being. For students primarily, the proper amount of sleep can "help stay focused, improve concentration, and improve academic performance".
The proper amount of sleep is dependent on how old the student is, but it is safe to say that anywhere between 8-10 hours is a safe bet. For elementary, middle, and high schoolers.