My grandma used to make a large batch of pie filling, portion it into freezer bags, and then freeze each bag in a pie pan. Once it was frozen she'd pop the bag out of the pie pan and stack them in the freezer. They'd then be frozen in the correct shape and volume.
I don't know if she froze pie crusts.
. I never saw her do that. But I imagine you could do it the same way the freeze grocery store crusts.