He is a kid.
He will grow out of it. Nole was a bit silly too back then, though he was already a good kid. Don't seem like it's the same case with Tomic.
You make it sound like he can be excused because he's so young, when he's not really all that young. He's twenty years-old, it's time for him to grow up.
Besides, some kids are sensible! *cough* *cough*