Possible Clues:

• Impossibility for a monotheist
• Gallery to become busy
• Dieties
• Idols displayed in gallery
• As flies to wanton boys are we to the creators? Presumably this is where you'd hear that in theatre!
• Top place needs stuff bought — nothing to be missing
• "American __": Neil Gaiman novel
• Olympic VIPs
• 'In the theatre not for hire, by the sound of it (4)'
• Nectar drinkers