The phrase originates from myth that cats have the ability to escape death because of their dexterity and agility. These old tales made people believe cats could literally have nine lives.
Pro Tip 2/3
Figurative Use
Used figuratively for people or things that survive risky situations, not literally having multiple lives. He walked away from that crash; he really does have nine lives.
Pro Tip 3/3
Cultural Reference
Common in Western contexts and may be understood differently or not at all in other cultures. In some cultures, the idea of having nine lives might not have the same meaning.