In a medium bowl, stir together crumbs, sugar, and melted butter until combined and moistened. Using your fingers, press the mixture into the bottom of a 9-inch pie pan and up the sides to form an even layer. Cover with plastic wrap and place in the fridge to chill for one hour, until firm (or, optional - for a crispier crust, bake the crust at 350ºF for 5 minutes. Cool before filling).
Using a mixer fitted with the whisk attachment, whisk together heavy cream, sugar, and vanilla extract on high speed until soft peaks form. Avoid overbeating. Spread whipped cream over bananas. Refrigerate for at least 3 hours before serving. Pie will keep for up to 3 days in the fridge.
* To make crumbs, pulse biscuits in a food processor until finely ground. You can pulse the sugar along with the biscuits in the food processor.