Yes you do need to thaw out frozen pie crust before baking it.
The frozen pie crust needs to be thawed out before baking it so that it's pliable and also allow you to crimp the top dough and bottom dough together properly.
You can reheat a frozen cooked pie or bake a pie from frozen if it's already put together but the pie crust needs to be thawed before you bake it and work with it.
The best way to reheat a frozen cooked pie is to reheat the frozen cooked pie in the oven.
Preheat the oven to 375 F and then once the oven is heated up you can place the frozen cooked pie in the oven on the middle rack.
Allow the pie to sit in the heated oven for 10 to 15 minutes to thaw and heat up.
Just make sure to keep an eye on it and check it often so that it does nut overcook and burn.
It's also better to remove the frozen cooked pie from the freezer and put it in the refrigerator overnight to allow the frozen pie to thaw out.
Then reheat the cooked pie in the oven for 5 to 10 minutes.
Having the frozen pie thawed out first prevents it from overcooking and possibly burning and it takes less time to reheat the pie from thawed than it does from frozen.