Are there quotes showing Odysseus' intelligence besides when he gives the Cyclops wine or disguises himself to test everyone's loyalty?
Good job in identifying one of the things that separates Odysseus from other heroes in Greek mythology (e.g., Hercules). It's not that he isn't strong; it's that he has brains and brawn. Homer announces it in the opening line of the poem: "Sing to me of the man, Muse, the man of twists and turns" (I, 1; Fagles trans.). You might also note in your essay that the reason Athena likes Odysseus so much is particularly because of his cleverness. When she meets up with him in Ithaca in book 13, she states: "'Always the same, your wary turn of mind,' / Athena exclaimed, her glances flashing warmly. / 'That's why I can't forsake you in your troubles'"(XIII, 374-376). What I find so delightful about the Odyssey is that Odysseus has to rely on his wits to get him out of trouble almost as often as anything else; it makes him more human than a Perseus, for example.
Odysseus creates a plan that will save his men from the Sirens. He has his crew put wax in their ears so that they cannot hear the Sirens.
Next, Odysseus has his crew tie him to the mast of the ship. His ears are not plugged with wax. He can hear the Sirens but cannot give in to their luring because he is tied to the mast.
In this, Odysseus proves his intelligence. He was witty and clever.
Also, another instance in the epic that proves his intelligence is when he was on Calypso's Island. He does not tell her he misses his wife because she will be jealous and not help him get home. Instead, he pleads with her that he is homesick for his homeland. He realizes that she will be more willing to help him if he is only homesick and not missing his wife. He is very wise in concealing the truth form Calypso.