nine: the cardinal number nine
This is simply the number nine. Like our own "nine," it counts things: nine people, nine cities, nine measures, nine years. It is one word with one job, and there is nothing hidden or symbolic behind it.
Most of its appearances are plain bookkeeping. It tallies the years a person lived (Adam's days came to nine hundred and thirty), the size of a group or an army, the number of towns in a tribe's territory, or amounts of gold and silver. It also fixes dates, naming the ninth year of a king's reign or the ninth day or month when something happened.
It often joins other number words to build larger figures, the way English stacks "nine" into "ninety" or "nineteen" or "nine hundred." In those places it is still just the same number nine, doing its part in a bigger count rather than carrying any meaning of its own.