A diet change can cause it, and you really need to keep human food away from him. It causes two problems. Sometimes it simply is not good for him, and secondly, it makes him a beggar at the table. Overeating results in a fat cat. A little bit of cheese is not all that bad (mine like it), but skip the lunch meat. It is often bad enough for humans, let alone giving it to a cat. LOL

As far as dry versus wet food, that argument will go on forever. With plenty of water available, a dry food diet is no worse than a wet food diet, assuming equal quality.
References :

I'm just really jumping in to suggest you consider changing his diet. You don't mention what you're feeding, but I'm going to guess it's dry food.

Dry food isn't good for any cats (in spite of the fact that it's very popular) but it can be especially bad for males who are much more prone to urinary issues.

At the very least, switch him to any brand of canned food. At the very best, switch him to a good canned food.

That won't cure a UTI but will help prevent future ones, will dilute the urine so it won't smell as bad, and will benefit your kitten in tons of other ways.

From my blog:
This is not my area of expertise, but this has been my experience: As a kitten, Poppy developed both a weight problem and a UTI. My vet told me to start feeding her special food which he happily sold me *gulp*. Poppy refused to eat it. Back then I was less aware of how to get cats to eat new foods, so I just said the hell with it and bought Purina's urinary health food, mixed with weight management. She ate that from then until she was 2 years old. She never had another UTI, so that tells me that the overpriced CRAP the vets sell you are typically unnecessary. The grocery store crap is just as good.

For various reasons, I soon thereafter began researching cat nutrition. I learned about the benefits of wet food, and found that in many cases, that's all that's required to prevent future UTI's. Even the crappy brands like Friskies would be better than dry food!

I don't claim to be a vet, vet tech, vet student or anything like that. But I know how to research and examine results. I've read a bit on this topic which is how I've reached the conclusions I have.

At the very least, were I to have another cat with urinary problems, I'd sooner try them on a GOOD QUALITY canned food before shelling out the dough for a "prescription" dry food (or even their canned varieties). That's because I believe that good nutrition and species appropriate food is much more likely to keep a cat healthy than something designed to change their chemical composition.
References :
Urinary Tract Disorders in Cats: http://www.littlebigcat.com/index.php?action=library&act=show&item=017
Why cats need canned food: http://www.littlebigcat.com/index.php?action=library&act=show&item=whycatsnee...