I doubt if they launched their best, it would do much; the Israelis have a very dense anti-air system. You will have to remove that somehow and then do what you need. But from where things stand, just lobbing a missile with an Israeli search and track system in place is an inefficient form of attack. Now, cruise missiles, and if they have stealth, one is a different story, which I doubt Iran is that far into this either.
9 direct hits were seen last time and that was just a "demonstration" attack.
Remember once they have a certain number of missiles heading at targets in the entity at any one time, the Zio-US system becomes saturated and simply cannot cope anymore.
Shoot hundreds of your older and about to be obsolette ballistic missiles to waste the ABM loads first, and then spank with the more modern and accurate missiles.
A full on attack using ballistic missiles and stealthy cruise missiles fired by a combined Iran/Hezbollah attack would have overwhelmed the defences and caused absolute mayhem and chaos.