The MOP is huge, so huge only the B-52 and the B-2 can carry it.
http://www.defenseindustrydaily.com/mopping-up-the-usas-30000-pound-bomb-03172/
I suspect news reports like this one are to provide a smoke-screen/cover for US actions in support an attack on Iran. You see, in my guess and the way I would do it, the US would fly the B-2 (low profile) as part of an Israeli attack. The US B-2 drops the MOP that destroys the deeply buried bunkers/facilities while at the same time the Israelis attack the entrances of the buried Iranian nuclear facilities to entomb the rest.
Follow with shaped rdx shelled U235 with PU core and infiltrate what's left with neutrons.
Plausible deniability of radioactive half life footprint due to the nature of the target.
Nothing living will survive. No one would ever know.
I think that C-130s can drop MOPs as well. They were the initial delivery platform for MOAB and the primary one for the old BLU daisy cutters. Deployment method I’d to roll them out the back with the Herk in a slight climb, then allow gravity and GPS do the rest.
The sanity of relying on a C-130 as the delivery platform in a high threat environment is another matter entirely.