I think it's safe to say that Tom Izzo is for sure staying at Michigan State. While I understand why some may be skeptical until something official comes out, there are just so many different sources reporting the news that it seems almost impossible for it to not be true.
In addition to WDIV and WILX, the following sources are now reporting that Izzo will stay at MSU:
Michigan State trustee George Perles via The State News:
BREAKING: MSU Trustee George Perles says his sources tell him Izzo is staying at MSU.
#Izzo told team at 6:45 meeting he was staying. Confirmed by source in the room.
Looks like this story is about as confirmed as confirmed can get without hearing from Tom Izzo himself.