I am a certified teacher, but not currently teaching. I called the Dolphin desk directly to clarify, since obviously I don't have pay stubs, and they said all that mattered was being a teacher with a current certificate.
Incidently, before I finished my degree, I was working in a school district as a substitute teacher and my paychecks were paid out of the same account as the regular teachers. (At least in my state, K-12 subs could have a college degree in ANY subject -- no teaching background or certificate is required.) If the S & D will accept pay stubs as well as certificates, then it sounds like non-certified substitute teachers could qualify as well, though I doubt that the program was designed to include subs. (Personally, I don't want to take any chances, so I'm bringing my state license.)