Originally Posted by doodlebug
The worse part is that these people don't care about the cat, they've gone away for a week at a time and intentionally left the cat outside.
If they're going to neglect the cat, I'd skip to the trap and rehome option. Why not contact a local rescue to see if they have space for him? Is he altered yet? If not, even more reason to do so, since summer is a busy time for kittens.
The Super Soaker is not going to work well. The cat can see and smell you, and will just hide until you're not on the porch. Unless you're going to camp out there all day, the moment you go to do something else it'll be back. Had a similar situation with my yard a long time ago. Sorry. You could try using the following things to keep the cat away:
Cayenne pepper, bobcat or coyote urine, or citrus oils/plants. They also sell a cat-repelling plant but some cats aren't affected by them.
If the cat is causing actual damage to your property, torn screens, vet bills, poo on the lawn, then you can have the authorities intervene. Just document the incidents and get a picture of the animal in the act. Keep receipts for screen repairs, vet bills and yard cleanup. Even if you clean the poo up yourself, be sure to document how much an equivalent pooper scooper service would have cost you because your services still have a value.
As long as they do not have sufficient fencing/restraint, and from your description it sounds as if they don't, then they are liable for any damage their cat causes. Because the law views animals as property, your cats injuries count too. However, taking this route might cause some neighbourly tensions.