In this bridge between kittenhood and senior age, your cat will still have some traces left of a younger cat: playfulness, energy, etc. But, they will have established more routines, and since they’re more comfortable with you and your home. If they’ve been socialized young, they will most likely continue to be social, but there are exceptions of course. Cats are quite independent in their nature, especially at this more mature stage, and you will see more of their more solidified personality come out during this time of life. You can get your cat neutered in this stage, but be sure to check with your vet to know how to handle the cat post-surgery. They may gain a bit of weight after the procedure is over.
You shouldn’t have to worry about litter box problems with this age of cat, and if so, please contact your vet for help with this. In terms of feeding, be sure to not overfeed the cat, and make sure the food is fulfilling all of their needs. You can test out a few different types of foods to figure out with they like best and what gives them the most energy. You will need to make the transition from kitten to adult food. Keep taking your adult cat for regular appointments, and as they grow older, your vet will advise you as to how often they need to come in. Your cat may need to be reminded of your rules still from time to time, but that is true of all stages.