So I've been thinking a bit about the bunker busting capabilities of the Israeli air force. I don't know exactly what they have in inventory, but they certainly could have GBU-72 bombs, which are 5,000 lb bunker busters and can be carried by F-15's, of which Israel has quite a few. The GBU-72 isn't our biggest bunker buster, though. That honor goes to the Massive Ordinance Penetrator (MOP), aka GBU-57. That sucker weighs 30,000 lbs and is way too big to be carried by an F-15. Officially, it can be carried by the B-2 and is planned for use with the B-21. Israel does not have the B-2 and probably won't ever get the B-21.
Does that mean that they can't use the MOP? Not necessarily. The MOP is well within the weight limit of the C-130 cargo plane. The C-130 isn't specifically designed as a bomber, but it is designed to allow cargo to be pushed out the back during flight. And it has been used to drop the GBU-43 MOAB in this manner. The MOAB isn't a bunker buster, but it is a really big bomb, about 22,000 lbs. The MOP is heavier, but it's also shorter (~20 ft vs ~30 ft), so fitting one inside a C-130 should be possible. Technically speaking, there's really no reason a C-130 couldn't drop a MOP. And Israel has C-130's.
So, why isn't this a standard option already? Well, in most cases where you would want to hit a target that needs a MOP, the target probably has air defenses as well. And the C-130 is NOT a very survivable aircraft in contested airspace (unlike the B-2 and B-21). But right now, Iran is not contested air space. Right now, Iran's air defenses have been disabled. Now, you can't just throw something like a MOP in the back of a C-130 and expect it to work same day. You would need to design a sled for launching, integrate control software into your aircraft, etc. in order to make it happen. Which isn't terribly complex, but also not a one-day project. But it's not inconceivable that this work has already been done. It's not outside the realm of possibility that Israel has the option to drop MOPs on Iran. But do they have that option? I do not know. And if they did, they wouldn't say.