My T8 I bought with the divider AND the shelf. Unless they changed design, if you get the divider you will actually get 2 separate shelves, so they CAN go in with the divider. And, when you remove the divider, you would then have 2 shelves next to each other.
I like the shelve, but I don't really use it anymore. I think there are cooler more natural looking items you can add inside for climbing or basking.