3, 6 & 9 are outside of the Powers of 2 Binary System and the Vortex system of mathematics.
They are considered to represent the 3rd and 4th dimension.
https:/ /truththeory.com/2016/11/25/teslas-secret-behind-numbers-3-6-9-finally-revealed/
Symbol of Enlightenment
9 Symbolizes (which is the ruler of the 3 and the 6)
Symbolize the plenitude of talents, the reward of the tests.
Symbol of the creation and the life as a rhythm and development.
As a product of 3 x 3, it is the expression of the perfection, the symbol of the virile power, in addition to be associated to the couple.
Nine is the number of the one who accomplishes the divine will. According to the Cabal, it is also the number of the achievement.
The freemasons have made it the eternal number of human immortality.