You can use a turbo controller for this but it's a little tricky to set up to work continuously.
Setup a local match with a 2nd controller with unlimited time, goals and balls that come out.
Every time you knock a ball off the center another spawns.
Move the 2nd controller out of the way and line up your shooter with the ball.
Turbo A and it will keep shooting. It kicks you back when you shoot so you need to line up correctly and have it push you against the wall. If you have it line up perfectly in the middle it will keep shooting and pushing balls right into the goal or else it might shoot them off to a side and balls will keep piling up but eventually will start going into the goal as the pile grows bigger.
Unfortunately when the balls pile up sometimes it blocks from having a new ball spawn so you should check it often.
I go over this in my achievement review/tips video at 9:55
Turbo Controller Instructions:
There's no X1 turbo controller currently but you can use your 360 turbo controller by plugging it into your PC and streaming your XboxOne through Windows10.