I went on the 6/15-6/22 Alaska sailing this year. We did Express Walk-Off, was announced to disembark around 7:45a.
We got to the lobby around 7:50a and a line had already formed. It took us about 5-10 min standing in line to get off the ship & about 10-15 min in the line up the gangway & through the terminal. Customs took 2 mins, walking to get a cab took 2 min, & standing in taxi line took 1 min before we were packing up the bags in the cab.
All in all, it took us about 20-25 min from the time we got in line on the ship to the moment we were in the cab & driving out of the port terminal.
And I agree with the previous poster - if you can, push back the breakfast time. Remember that you disembark on a weekday so there could be more traffic than usual. Even without traffic, I think it's a 30 min drive from Canada Place port to Grouse Mtn.
I'd suggest to stand in "line" with your bags around 7a, so you can be one of the first to get off the ship.
Good luck!
P.S. - Make sure to have your kttw cards ready --- they won't let you off the ship unless they scan your card. *I saw people scrambling because they had packed them in a bag or purse...this will delay you.*