Responses
Yes, he missed them and I think that he had just been acting strong all the way but once he finally got home to his safe place, he was able to relax and show his real feelings. At school he seemed mature and independent, like as if he had adapted without issue but at home he was able to act like the kid he is.
At least that's how I saw it.

Why did mori cry? Is it because he missed his family once he saw his past self staring into space and alone in the yard?