Other mistake: The Reporter states it has been 25 years "almost to the day" since Billy and Stu died (1996), making it September 2021. Tara is a high school senior, and her older sister, Sam, Billy's daughter, is stated multiple times as 5 years older, 23 at best. Many Easter eggs on Richie's laptop state STAB 8 is a 2021 release, which was "last year" according to Sam and Mindy in separate scenes, making the film set 2022, 26 years later. Sam is 1-2 years younger than she should be, or Tara is 20. (00:57:14 - 01:47:18)
Suggested correction: The Scream movies never say at all specifically when they take place. For you to say "September" when the movie never ever for any reason said the month it was taking place in is just a lie and not a mistake. Also just because Mindy said "last year" doesn't mean anything. She could have meant last school year, since kids in school generally use their schooling as the basis for "this year/last year." I've already heard people say last years Scream even thought it's still 2022.
It's pretty comprehensively covered that they're in September, based on the killing of Maureen and the 1996 Scream killings which takes place almost exactly a year later: https://scream.fandom.com/wiki/Timeline.
No. They never say this in the film, at all, there is no evidence of when it takes place. The wiki link you sent is objectively pure speculation by whoever wrote it.