If it takes you an hour to get there on a normal day, leave 45 minutes to an hour before that. With the Ikon pass including Solitude now the canyon has been packed this year.
Add the Holiday and the weather, it’s going to be worse. Also, if you get there between 9 and 9:30, there is a good chance they’ll have the parking lot full and closed and you’ll have to find road parking and hike in.