Why do cats have 9 lives?

Is a legend. So.
A cat thrown from 4th floor to land on my feet. Same on the 10th floor. This does not mean that the cat will survive the fall. Depends on many factors, how heavy the cat that land surface, etc..

How many lives does a cat have

Starting from the idea popular (tradition) that a cat (demonic animal) is about 7 lives (other speak 11), someone asked, "How many lives has the cat? - really"
The answer is one: a life. A single one life, that's all.
 Legends have their charm but the reality is different than dreams and ancient stories.