iCloud Drive and iCloud photo library are separate - the photos won't appear in your drive. The Mac Photos app won't be out until early 2015 but photo library will be available next month on iOS, in the time between the two releases you'll probably have to rely on iCloud.com to view your photo library on your computer..
I'm wondering if I should sync my photos from my macbook iPhoto when I get the phone in a few days, or wait until the Photos app comes out.
It seems that if I were to sync my photos to the phone, I would have two libraries. My iPhoto library on the mac, then my phone photo library. When the photos app comes out for macbook next year, I'm worried it's going to be a mess having the two libraries merge.