How to fit pie dough without stretching it
Measure the route down the sides and across the base before trimming or building the rim.
Two dishes sold as nine-inch pie plates can have different depths and slopes. Before rolling, lay a piece of string across the inside surface: start at one rim, follow the wall down, cross the bottom and continue up the other side. Measure that length, then allow the extra overhang your recipe needs for its edge. The rim-to-rim diameter alone misses the depth.
Center the rolled dough over the plate. Lift the edge nearest you and let the dough settle into the corner where the floor meets the wall. Work around the plate a little at a time. Stretching the pastry down into the corners makes it look like it fits, but it can retract in the oven. If the sheet is plainly too small, lift it back out to roll it a little wider.
Trim and form the edge only after the dough sits naturally against the plate. Give it the rest and chilling time in the recipe. For an empty shell, also follow its directions for lining and weights; fitting the pastry well solves a different part of the problem from supporting it while it bakes.