It might be a natural thing. I have no idea how Kaji started to catch, especially since for the first 6 months he showed no interest in playing with the ball at all, or playing in general. Once he started catching, I added a command to it and he is a catching fiend! I think he should try out to be an outfielder for the dodgers because he's just that good. We also have a much bigger plush soccer ball and I'm trying to teach him to hit that with his head like soccer players too. He does it sometimes and gets lots of praise for it, but most of the time he catches it.
I can't seem to teach him soccer is a different sport.