Yes, and some schools have a dozen "valedictorians." Mathematically possible, but highly unprobable.
I went to a graduation in June. The valedictorian gave a speech. It was a rah-rah sis-boom-bah speech. I reckon good grades aren’t necessarily a standard for impressive public speaking, or even content selection. Perhaps a thespian should be selected to recite something with a little meat in it.