Israel has an established track record with bombing nuclear facilities, such as in Baghdad in 1981. It was even done on a Sunday to prevent workers from being injured, and, was bombed before going into production to avoid any nuclear health related injuries to those in the area. Israels justification in 1981 is the same as it is today towards Iran. They will not allow themselves to be attacked by nuclear weapons. And as Iran is following suit, Iraq claimed it was not for nuclear weapons.
Its been done before, Israel is capable of doing it again and bombing all the facilities in one strike.