What is an example in the Odyssey of destiny ultimately lying in the hands of the gods?
For example, in Book 24, Telemachos aims his spear at Eupeithes' head, he invokes the help of the gods so that his aim may be fatal. He made the decision to throw the spear, but it was a god rendered the throw fatal.
Are there any more examples in the Odyssey like this?
At various points in Homer's Odyssey, we see the gods bringing about a particular outcome or preventing a particular outcome. The student has given an example from the end of the epic, where Telemachus, with inspiration from Athene, kills Eupeithes.
A similar divine intervention in a battle scene occurs in Odyssey 22, where six of the suitors try to attack Odysseus simultaneously with their spears. As in Book 24, Athene again intervenes ("but Athene deflected most of them"; A.S. Kline translation)
Near the end of Odyssey 12, after Zeus destroys Odysseus' remaining ship and brings about the deaths of his remaining men, Zeus then saves Odysseus by preventing the Scylla from noticing him: "The Father of men and gods prevented Scylla noticing me, or I would never have escaped utter disaster."
And, of course, Odysseus never would have made it home if it were not in accordance with the plans of the gods. Thus, in Odyssey 1, Zeus tells Athene:
Come, let all here plan how he might come home: then Poseidon will relent, since he’ll not be able to contend, alone, against all the deathless gods together.
So, as we can see, the success or failure of mortals in the Odyssey frequently depends on the backing or opposition of the gods.