Training them to potty IN their crate is totally backwards from what you want to teach him. If you teach him this now, he will always do it. He is small and has a tiny bladder, you chose to buy him and take care of him. Just as human baby's need attention in the middle of the night, so do baby dogs. You need to let him out regularly until he is old enough to hold it longer. Eventually he will.

He has a lot of energy - maybe your need to play fetch with him to wear him out.