UTI (Urinary Tract Infection) or a blockage - Sometimes, if they have a UTI, it will make them “go” outside the box because they associate the box with pain when urinating.
Diabetes - while diabetes can affect any cat, it tends to strike in middle age, especially if your kitty is overweight. High glucose levels can lead to excessive thirst and urination, including outside the litter box.
Urinary Crystals – Like a bladder infection – these can cause a lot of pain, and the kitty starts associating the pain with the litter box. Go see a vet, just in case!
DECLAWED? – Has this kitten been declawed? Declawed cats often have litter box issues as various litters hurt their paws now, so something to consider IF he has been declawed.
Hormonal – If your kitty isn’t spayed or neutered. Some females will urinate to “advertise” that they are in heat. And males will spray to mark their territory.
Message – The cat is trying to “tell” you something. It might be that they’re not happy with their litter box or that there’s another issue they’re trying to communicate.