Why 9?, or: an introduction for skeptics

There are a lot of reasons why 9 is the best number. It is rather clear for many, but i will try to break it down.

It is the first truly composite odd number (1 only has one factor, so it isn't truly composite).
Multiples of 3 add to a multiple of 3, but multiples of 9 add back to the greatest number.
It is square (yes).
Logarithmically, it's a very useful number.
It looks cool (undeniable).
My thoughts are dominated by it. When I look at the time, i think of how it can be added together to be 9, and if it can't be, i think of how to fix that.
It is the best and most iconic square. A 3x3 square is just the best. I could not tell you why.
It is a very strong number.
It is always present before the next iteration of ten or higher order of magnitude. As such it is the end of things.
Numbers look better when next to it.
Dividing a number by 9 will give you the number (subtracted by 9 if over 9) repeating as the decimal making it essentially a way to understand base 9.
There are 9 planets; pluto or planet 9 are both fine.
There are 9 planet gods in hinduism and hinduism is cool.