Iran could not close the strait for long no matter how much exercise it gets. Whatever navy it has will be gone if it does. Shore batteries will be destroyed. Israel probably could not shut down the nuclear program for long but could do lots of damage. It is all made of the stuff that makes the grass grow green.
Saudi FM: We hope Iran uses sanction relief for development, not nefarious activities (Reuters)
from the article: Revolutionary Guard starts military exercise in Iran's south