"Hybrid certified" is a tricky designation. ASE, the national certifying body for auto repair, has no hybrid test currently, and therefore no certification. I know they are working on a test now, but even then it's no guarantee the individual can fix the car.
Dealers have certifications, but these will be within their individual makes. A few enterprising instructors had divined their own "hybrid certifications" but this is largely used to sell their classes, not to select out qualified personnel.
Your best bet by far is to inform yourself on what your vehicle needs--read the maintenance manual and research any problems as they arise--and talk to the mechanic of your choice about their comfort with the technology. The A techs in any region have sought out some hybrid training by now and the honest ones will tell you when they've reached their limits to help.
By in large any technician that's strong in the vehicle make (Toyota, Honda, Ford, et al.)--I'm talking the journeyman tech with real enthusiasm--will be able to negotiate unforeseen repairs as they arise and service the car properly at the least expense. The dealer can be hit or miss. Again, your own personal education on the technology will pay off in the long run.