For the sauce, in a large saucepan, combine the pineapple juice and tapioca; let stand for 5 minutes. Stir in the sugar. Bring to a boil; cook and stir for 2 minutes or until slightly thickened. Add blueberries. Return to a boil; cook and stir for 5-10 minutes or until sauce reaches desired thickness.
For pancakes, in a large bowl, combine the biscuit mix, egg, milk and vanilla. Fold in the bananas. Pour batter by 1/4 cupfuls onto a greased hot griddle. Turn when bubbles form on top cook until second side is golden brown. Serve with blueberry sauce.