Yes puff pastry can be used for the base of a pie.
You can use puff pastry to bake pies with and it will turn out just fine just like when you used regular pie crust.
I've baked pies using puff pastry as the base of a pie and it turned out great.
Puff Pastry does make great Pie Crusts especially for pies such as Fruit Pies.
To use Puff Pastry for pies just roll out frozen or homemade puff pastry to 1/8-inch thick and follow the instructions for par-baking regular pie dough.
To keep the bottom of your puff pastry from getting soggy make sure to preheat the oven to 400 F degrees and use a thick baking pan and brush the baking pan with a layer of Apricot Jam.
Most Professional Chefs who bake Puff Pastry will layer the baking pan or baking sheet with a layer of Apricot Jam which works wonders to prevent the bottom of the Puff Pastry From Becoming Soggy.
It has worked great for me after I learned to use the Apricot Jam on the bottom of the pan.
You can also brush the bottom of the baking sheet with eggs as well which also helps the puff pastry keep from becoming soggy as well.
Yes you do Thaw out Puff Pastry before baking it.
You must Thaw Puff Pastry Before Baking the puff pastry or it won't bake and turn out correctly.
Thawing the Puff Pastry out allows the Pastry to become pliable without softening too much.
When Thawing the Puff Pastry Out before baking it it's best to thaw the Puff Pastry out overnight in the fridge and then it will be ready the next morning to bake.
When you don't Thaw Puff Pastry Before baking it the Puff Pastry will not hold it's shape when baked and may also fall apart.
So take the time to allow the Puff Pastry To Thaw out first and then bake it.