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.
duodecimal (base 12)
The duodecimal system (also known as base 12 or dozenal) is a positional notation numeral system using twelve as its base.