I’ve heard the expression “pie” for pizza used mostly around the Northeast.
Pizza pie is redundant since pizza is the word for pie in Italian. Technically, any flat round baked product with a topping or filling is known as pizza in Italy. Pizza Napoletana is the kind that is most familiar to us.
Some of the more common “pizzas” in Italy:
pizza bianca
pizza alla verdua
pizza alla Romana
pizza Pasqualina