What you said is not an indoctrination technique. It just defines what indoctrination is, sort of. Indoctrination is the process of teaching a person or group to accept a set of beliefs uncritically. I.e. to have them not think about what they're being led to believe by keeping their attention elsewhere while inserting the beliefs they want them to have. One common technique used in secret societies and occult schools is to introduce information or visuals that appear to have some sort of relevant meaning, and then to explain it in a way that conforms to their already established beliefs but also expands on them enough to change some aspect of them, always taking them further into the desired belief system and away from their previous one. This is done slowly over time and only moves forward to the next small change when the previous one is shown to have been accepted. Throughout the process, the mystique of the information must always be applied in order to keep the mind of the initiate attentive and open to accepting new ideas. It's a mild form of hypnosis that breaks down the barriers of logical thinking in order that the new information will be accepted without thought. The visuals in that video and others like it are used this way in occult teachings. The mystery of the number 9 is nothing spectacular. If we used base-7 (or any other base number system) rather than base-10, the same relationships would be there. Every configuration would add up to 7. It's just the way numbers work.