The rumor comes from Nintendo Life's "trusted sources," which have a track record for accuracy. The last two Directs were accurately predicted by the same source. This claim also coincides with the same rumors that surfaced last week, though were quickly disregarded for lack of evidence or reliability.
Further reinforcing the idea is a new tweet by the Animal Crossing UK Twitter account, which teases the idea of Splatoon content in the popular Animal Crossing Pocket Camp mobile game.
"Goodness! What's going on here? We're supposed to be getting a sneak peek at what's to comebut all I see are those bright colors. Hmmmsomething about this does look familiar. What could it be?"
A number of leaks pertaining to Nintendo titles have appeared over the last few days. These were most likely planned for a normal reveal alongside the Direct, but were hastily hidden after the delay was announced. This included the Spyro: Reignited Trilogy for Nintendo Switch, and the upcoming Yoshi game's proper title.
The best thing about rumors of this nature is that we'll find out if it's true soon enough.
Nintendo has now confirmed the date and time of the event on social media.
"The Nintendo Direct initially scheduled for 9/6 will now debut this Thursday, 9/13, at 3pm PT. The broadcast will last approximately 35 minutes, and will feature information about upcoming Nintendo #3DS and #NintendoSwitch titles."
You can watch the event live right here.