There are things you can buy to put down that will make cats avoid an area.
The kitten, if it comes back, just do what you can. Feed it and if you're wealthy take it to a vet. If not just do the best you can. Are these cats really yours... and spayed/neutered?
There are people who will abandon or dump a cat or dog without hesitation. It happens here frequently. We do the best we can. Anyway... that may be where the kitten came from if it doesn't belong to one of your regulars. Good luck