BCBS doesn't require additional certification for telehealth. Not all BCBS plans cover telehealth though so you have to check with each plan. The general rule of thumb is that when you verify benefits, if it states that Telehealth is covered, it is, and if it doesn't say anything, it's not. But maybe with the Governor's ruling, they'll cover it for everyone?
BCBS is not required to expand telehealth coverage for OON providers based on the text of the Governor's order. If you are OON and bill directly, telehealth coverage will be based on client's plan. Alternatively, if you provide the client with a superbill, there is no indication on it whether the session was in person or via telehealth, so this may work.