It can be done in a day. It's a lot easier and more fun to do on skis. Stash them at the top of the notch and boot up the final 400 (unless the coverage is good and you can ski it). Otherwise, slog it out on snowshoes.
Sounds like you've done the requisite training and courses, which is great. You won't find a crevasse or glacier on Whitney, but you may find avalanches. Have you taken an avy course?
The Sierra snowpack is typically a lot more stable than WA, UT, CO, but they still happen. Be mindful of avalanches, especially in the lower north fork (lone pine creek) drainage.
