Once standing, get the player to repeat the same action, namely, sending the ball out of his hands but this time let it go up about six feet. Now have him kick the ball with bent knee straight up.
Add A Variation
Bring in a variation by having your player follow the above exercise by introducing a bounce with each kick. The kicking height should be maintained at 6 feet. The whole idea is to learn to control the ball, not display force.
The next step after achieving the above is to get the player to kick the ball to a fellow player. Now, the ball should be struck when it is on a downward path. He should not allow the ball to go higher than his own height and kick the soccer ball it with a spin. Repeatedly practicing this will bring in control as well as power now.
The entire exercise can be done with shoes and socks on. Your player will find that it is easier to do the exercise. You will have to be patient while teaching youth soccer players how to kick a soccer ball as different players learn at different paces.