Whisk pastry flour, all-purpose flour, baking powder, 1/2 teaspoon cinnamon, allspice, salt, nutmeg, ginger, and baking soda together in a bowl. Cut cold butter into flour mixture using a pastry blender or 2 knives until mixture resembles small crumbs.
Mix 1/2 cup pumpkin puree, sour cream, white sugar, and egg together in a separate bowl; stir into flour mixture just until dough forms. Gently roll dough into a circle on a floured work surface and cut into wedges or use fall-inspired cookie cutters. Arrange scones on a baking sheet.
Bake in the preheated oven until lightly browned, about 15 minutes.
Mix confectioners' sugar, 1 tablespoon pumpkin puree, and 1/4 teaspoon cinnamon together in a bowl until glaze is smooth; spread over warm scones.