In a large bowl, mix together the cream cheese and sugar until light. Prepare the whipped topping mix according to package instructions, and fold into the cream cheese mixture.
Place a layer of sliced banana into the bottom of each pie shell. Spoon half of the cream cheese mixture into each pie, and spread evenly. Spoon half of the blueberry pie filling over each pie in an even layer. Cover the tops of the pies with the thawed frozen whipped topping. Chill until serving.