Preheat oven to 375°F. In a 9-inch pie plate, toss blueberries with 1/4 cup of the sugar and 1 tablespoon of the flour; spread evenly in pie plate. In a medium bowl, combine remaining 8 tablespoons (1/2 cup) flour, the oats, walnuts, pumpkin pie spice and remaining 1/4 cup sugar. Using a pastry blender or two knives, cut in butter until moist crumbs form. With your fingers, press together crumbs to make large chunks; place on top of blueberries. Bake in top third of oven until topping is browned, about 20 minutes; cool on a rack.Preheat oven to 375°F. Spray bottom and side of a 9-inch pie plate with vegetable cooking spray; sprinkle with breadcrumbs and tilt to cover evenly. Preheat oven to 375°F. In a 9-inch pie plate, toss blueberries with 1/4 cup of the sugar and 1 tablespoon of the flour; spread evenly in pie plate. In a medium bowl, combine remaining 8 tablespoons (1/2 cup) flour, the oats, walnuts, pumpkin pie spice and remaining 1/4 cup sugar. Using a pastry blender or two knives, cut in butter until moist crumbs form. With your fingers, press together crumbs to make large chunks; place on top of blueberries. Bake in top third of oven until topping is browned, about 20 minutes; cool on a rack.