Should bunker busters present a big cloud? Ideally it should penetrate into the ground before exploding.
Almost all of Iranian facilities are under extremely hard rocky mountains and likely 100's of meters deep with meters of highly reinforced concrete making up the building itself. So nothing can penetrate that deep. Nothing, not even tactical nuclear weapon. Though nuke would cause extremely high frequency high bandwidth vibrations which must be dissipated using some soft of well designed structural damping.
This conventional Jdam like attack was likely at the entrance of the facility which is on purpose designed to be collapsible in controlled manner so that rubble can be cleared easily after the attack yet acts as a seal for prolonged bombing while there, saving internal building structures. Additionally having certain collapsible sacrificial structures that guide and absorb the detonation energy also creates dust. The dust is likely due to entrance collapsing saving the internal building while still allowing some sort of auxiliary outlets (being blown up in the process) that guide the detonation energy away from internal building structures (e.g. concealed from above lateral tunnel openings ) that may be partially destroyed but also act as outlets after destruction for detonation waves for one or more bombs.
These likely to be hidden and sealed initially but as seals are blown up they act as guide wave so that blast waves can use them as an outlet (or outlets) in the process creating dust clouds. Among other things, this is one way to be able to protect the deep inner structures. The other way would be to have side entrance that allows blast waves to enter from one side and get out the the other while actual entrance is deep behind this side entrance like in US mountains. US nuclear safe mountain facility has diagrams online somewhere that explains this type well. Regardless, entrance still can collapse or be partially damaged, and dust clouds likely will rise. Due to being under extremely high temperature, smoke is normal as even rocks and cements burns at those heat levels.
Instead of attacking the entrance, they can try to penetrate the mountain itself from above. Though mountain rock may as well be too hard (or can hardened) for deeper penetration and can cause premature detonation. I doubt Israel or US would try that route. They don't have the capability to (not demonstrated one or even academically published one noting academic research is often far ahead in time than industry) to penetrate as deep as Iranian structures are. The energy requirements are immmense plus there is trade off, too much energy (e.g high velocity at impact) and bomb itself will disintegrate. Not enough and it won't penetrate.
US or Israel can't do it using JDams like weapons. Using Special ops is suicidal as Iran special forces can defend it or they can rig part of tunnels with sensors based high explosives devices, killing whoever tries to enter. One can come up easily with such solutions that are nearly impossible to defeat especially in hostile country where time is of the essences. Plus destroying a centrifuge facility won't make much difference. Its mosty symbolic and for propaganda. They can re-built new centrifuges and likely have enough stock piles alraedy elsewhere.