Goku's Energy Absorption

Does he half to raise his hands for energy absorption?

In order to perform Spirit Bomb, yes. Considering that's the way in which he always initiate the technique.

This reminds me of a question a little kid would ask.

Yep. Its right after the rule where you must scream the first time you get a new transformation and right before the rule which states all fights have to start off with a warm up phase in which the characters aren't trying.

He can also only get it if the subject is willing.

I see