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I swear is was called Fat Cat or somethng along those lines, if not the title it was on the title sequence intro theme, but I can't find anything to that name that fits
I'm not familiar with any cartoons about a well-rounded fat cat, so just incase your memories are mixed up: Fat Dog Mendoza is about a dog just like the cat described in this query, and some people on YouTube have mentioned it aired quite early in the day. That aired on Cartoon Network, though (in the UK, at least; I'm not sure where you live or if Fat Dog aired outside of the UK).
Unfortunately, I can only think of a few "close guesses".
The closest thing I can find to your description in plot terms would be Heathcliff. It's a bit older than the timeframe but I suppose it's possible it could have been repeated early in the morning during that period. Heathcliff wasn't that round though looked rounder from certain angles.
Old Tom was fairly round and from the right time period though had a female owner.
Eek from "Eek! The Cat" fulfils the shape requirements better but is the wrong colour and I don't recall having a young boy owner.
There was a character called Fat Cat on Chip 'n Dale: Rescue Rangers but that doesn't appear to fit your requirements so I imagine is just a coincidence.
Thank you both so much for helping! Spark Plug The Troper yes it is that exact show!!, my days of torture are over I was thinking cat all these years and it was just a hideous dog, I mean dog. But gheeze I don't remember it looking so terrifying.. Anyway thankkk youuuu!!!!
There was a tv show that was on in the late 90s really early on in the morning, I wanna say like 5 or 6 just before Tribe on channel 5 began but I'm not sure if it is the same channel. I'm pretty sure the cat was ginger and partner for the show was a young boy that owned him. I think the title sequence referenced something about him being as round as the world and him eating everything, needless to say this is really bugging me and anyone who knows what the heck I'm talking about please help me out, it's been tormenting me for years And it's not Garfield or any of the usual others, I'm not sure there were many episodes so maybe it's really obscure. The main thing I remember is that this cat was almost drawn literally round