ok, for the master of the runes ability, no you can not use two psychic shooting attacks. The base attack stat is purely for your melee attacks, the only units that can make multiple shooting attacks are montrous creatures, and vehicles. Sorry, its somewhere in the rule book, the ability is meant to give you the option to take multiple psychic powers to use during the game. It gives you versatility, some powers are good when your not in combat and other you can use when you are.
As for the murderous hurricane, you are right per what you posted as the codex saying. You would take the psychic test and if passed inflict 3d6 wounds directly to the target units, so you would just roll to wound. Hope that helps.