* Mount a 60 fps camera pointed at the pins.
* Continuously record a short looping buffer in memory (5 seconds would be more than enough).
* When the ball-trigger fires, wait an extra second, then freeze the buffer and play the buffer once at normal speed, then again at 1/4 speed.
* Finally, restart the recording loop.
If it's a dark alley, you could use a low-light camera such as an Arducam with the STARVIS IMX462 (no IR-cut) and if ambient light is still too low, add a few infrared floodlights. Having instant slow-mo every time the ball hits would be a crowd pleaser, especially with kids and casual venues. If one of my nearby alleys had this, I wouldn't go to any other alley.