Agreed with Jerry305.

You will likely not make the flight unless you leave the game early.

You will have absolutely no luggage? no carryon bags? if so take the airport express from the Fairmont Queen Elizabeth hotel which is really close to the ACC. If you need to pick up your carry-ons then keep in mind that the Sheraton is still a good fifteen minute walk away from the ACC.

Toronto traffic esp. the Gardiner Expressway (which is the route the AirportExpress takes) is horrendous.

Pearson (YYZ) is a terrible airport for clearing security, esp if you are flying back to the US, which you have not specified.