The bear problem is only at Whitney Portal, not up on the trail. Just put all your food in the bear-proof lockers at the parking lot at the trail head. The canisters keep mice and marmots out of your food when you camp at Outpost Camp or Trail Camp; bears will not bother you there.
Since you're coming for the first time, doing the switchbacks in daylight is good. The most dangerous part of the trail is people descending in the dark, losing the trail, and then slipping or falling.
Leave all your gear in Trail Camp that you don't need. If it is at all windy or stormy, put some rocks inside your tent so it won't blow away. Any food you don't take along should stay in the bear can.
