Man. I had trouble getting my snake to eat rats. I'll have to tell it that it should be willing to take on and eat a 3-4 lb kitten. Never mind the fact that most ball pythons never move above small rats, and even large rats are smaller than a kitten at any reasonable age.
As for 'no matter what size?' BALONELY. This is the kind of thing that makes my mother question the safety of my 15lb dog in a house with 1000 gram snakes. A 4-5 week old kitten MIGHT be in some kind of danger from a BP, but a BP taking on a 3-4-5lb cat? I just can't see it.
Kittens being a threat to the snake, yes. The other way around? Man, my snakes most be unusually finicky and all that stuff about BP being difficult to change food items on must be wrong - because a mouse to a rat (or asf to a mouse) is a lot closer than a rodent is to a cat.