The number 9 seems to be rather important in magick, but I’m not sure why. There are 9 Gatekeepers, 9 demonic kings, the Church of Satan had a council of Nine, as does the Temple of Set. There was even a reference to a council of Nine in Greek mythology.
The number 9 also has roots in the Norse system. Strange synchronicity, when I first started to really get into Norse related subjects, my dog who was pregnant at the time had a litter of nine puppies. I took it as a sign I was on a good path.