Stupid thing to do, but I can understand he was pissed off, time running out, and the ball-boy deliberately trying to run the clock. He certainly tried to hit the ball underneath the kid, but still you have to use your head. You just don't risk it.
Please, ball boy was playing keep away with a player on the field. The kid literally curled up in a ball doing a "you can't have" routine. So the player punted the ball out from under him. The ball boy does his best I've been killed overdramatic flop.
Crap like this is why i can't stand soccer games. I like the sport a lot, but the drama BS ridiculous. There should be a dozen ball boys and soccer balls. all game long I've seen crap load of issues with out of play balls. Win on the Field stop playing BS games.