Three times three. It is in this way symbolic of a trinity of trinities. Nine as a number is interesting when it is used in the basic mathematical processes. Any number added to Nine equals that number. Any number times Zero equals Zero.
Any number times Nine equals Nine.
No number can be divided by Zero. No number can be divided by nine without producing an infinite decimal. Understanding the symbolism of the nine gives meaning to the zero. Any attempt to analyze the zero results in nothing at all. The next level of understanding the numbers comes from the analyses of the addition itself.