base 9 is a positional numeral system with nine as its base. It uses 9 different digits for representing numbers. The digits for base 9 could be 0, 1, 2, 3, 4, 5, 6, 7, and 8.
quaternary (base 4)
Quaternary is the base-4 numeral system. It uses the digits 0, 1, 2 and 3 to represent any real number.