As of now, no. I've heard he's planning to graduate in May. Which would mean he'd need to stay in Columbus until May. No way on earth Miami takes all of his credits from OSU short of his last semester and gives him a degree. If he transfers now, there's no way he graduates in May (and probably not by August), therefore meaning he's not a grad transfer and therefore would not have immediate eligibility.
He absolutely can apply for a waiver but I don't know on what grounds. Apparently the NCAA is sympathetic to people who had their redshirts mismanaged (hence why Martin is apparently likely to get a waiver), but that doesn't seem to be the case with Martell.
My guess is he does not play in 2019.