I have a beautiful grey tabby, nearly 2 years old and roughly 10lbs, vet said he's the perfect weight for his build and is very healthy, so I've been going off his general build for how my younger male (roughly 7 months) should look. Seamus, the younger, is already the same size as Neville, the older, and I estimated when I got him that he'd be much bigger than Neville, since at 9 weeks he was nearly twice the size Neville was at the same age. However, I've been noticing that he's getting a little.... tubby. He's always been just slightly on the tubby side, as kittens seem to be at a young age, and the vet said he was healthy and a good size. I haven't been to the vet again yet (money has been a bit tight since the start of school, but I'm hoping to get him in in a couple weeks).
Seamus seems perfectly healthy. He's been growing nicely, eats and drinks regularly, and he's very active, often playing with my mom's puppy and racing around the house with Neville at night. He takes frequent naps during the day, usually with Neville, then immediately either wants attention or to play upon waking up. He's a wonderful cat, very playful and full of love. I'm a little concerned about his weight, though. It seems he's on his way to being overweight, if he isn't already, and I'm not quite sure what to do about it. Both cats are on kibble (they were on raw, however, I decided to switch them to kibble while they're still young as I plan to move abroad and take them with me, and raw could be an unreliable food source). They're both free fed and share a large bowl. I feed them Performatrin Ultra, it's grain and gluten free. They sometimes get fish (sardines, usually) and bits of raw food (Seamus usually licks the spoon right after the dogs' food is scooped).
Both cats have the exact same diet, and Seamus is actually more active than Neville. Is it possible that he just has a slow metabolism, or could there be something wrong health wise? I'm aiming to get him in for a check up as soon as possible, but any advice for now would be great.