>>9451455What a question!
Sadly, I won’t be able to answer each bit of it here since my knowledge is admittedly humble and it’s just so throughly layered.
3, 6, and 9 (as well as 12 and to a lesser degree 36) are deeply important numbers within occult tradition (particularly that of Kabbalah- a Jewish brand of mysticism) insofar as they are all dividents of 360 degrees. Primordial man, as you know, was capable of viewing the skies in three-hundred-and-sixty degrees, which is the origin for the modern calendar and astrological signs.
To vastly, vastly oversimplify (and for the sake of levity...), ‘three’ is oftentimes associated with the trichotomy of Mind, Body, and Soul- and by extension, various mythological archetypes such as Dionysus’ three faces, the Three Fates of the Hellenistic pantheon, and The Holy Trinity. The symbolism of the Trinity is more important to later Christian ‘gnostic’ groups such as the Cathars.
Because 3 is the codification of Mind, Body, and Soul- it has oftentimes been related to the ‘Root of Existence’, since these are the threefold lenses through which humans percieve the conscious and unconscious world.
On another note- in Kabbalah/Jewih Mysticism, the Tetragrammaton (that is, the true name of God, YHWH/Yahweh) is made up of three letters in English: Y, H, and W. This is a bastardization, however, since in the original language it is composed of FOUR letters: yodh, he, waw and he. They correspond to the first spoken words of God to Moses in accordance to sourcss such as the Old Testament: “I am that I am”. Since God is the ‘root of existence’, it is the only being within the world capable of justifyig its own existence- it simply IS.