You may need to worry about jitter on that pulse signal, for laser scanning you probably need something like
resulution of 10 minutes or arc or better, which at 10krpm is 1.6µs - if the signal from the motor has significant
jitter you'll have to implement a PLL to clean it up (either locking the motor to a quartz defined reference, as mentioned above, or locking a VCO to the physical motor). The mechanics have very low phase noise due to
the inertia of the rotor, and so a PLL can work wonders even from a fairly noisy
sync signal if the PLL bandwidth is low enough.
Anyway worth trying using the sync directly initially to see how much jitter you get - it might be OK for
your purposes, and its certainly simplest.