I checked Jim Jones's book, A Map of Mexico City Blues and found no easy reference to the 95 devils. Ditto for Nicosia's Memory Babe.
I asked a Buddhist monk and he told me that there are considered to be 96 heterodox schools of Buddhism. So perhaps in these passages Kerouac is suggesting the tearing down or knocking away of all but the one true teaching.
Then again, maybe it's a Shakespeare reference.
Will let you know if I learn anything else.