I grew up in the 90s and I remember being able to truncate the year down to just 2 numbers when talking about years within the current millennium. It seems like we’re still saying twenty before every year and I’m just wondering when that will change.
In UK I’ve mostly have heard ‘naughties’ for the decade sine about 1999. But I rarely heard “naughty X” as a year name unless someone was being even more deliberately daft. I’d say “oh” would be most common here after “two thousand and X” too in my experience.
I always thought that “'aught” was an American contraction of ‘naught’.
“aught” in old timey-English can mean “other” or “else” or even “anything”. In my local dialect we still say “owt” meaning “anything” as an opposite of “nowt” nothing".