It's an idiom, much like "you are pulling my hair". Are you actually pulling my hair? Of course not; taken literally, many English phrases make no sense. But th

It's an idiom, much like "you are pulling my hair". Are you actually pulling my hair? Of course not; taken literally, many English phrases make no sense. But they are common elements of the language and everyone understands them, so they aren't problematic. This is the same. Taken literally, "9x smaller" is nonsense, but everyone who hears that phrase knows exactly what mathematical operation you are referring to, thus it's a totally acceptable way to express that you mean to say 11.11% as large.