One could argue that the main trope in Pound's canto 116 is that of homecoming. In canto 1 the blind seer Tiresias prophesied that Odysseus would return "through spiteful Neptune." In other words, he would only be able to return home to Ithaca after facing the terrible wrath of the sea-god. Sure enough, Odysseus is subjected to Neptune's brutal vengeance, but once again our hero is saved, this time by squirrels and blue jays, the creatures that Pound observes from his prison cell in Italy.
Although there is a sense that Odysseus, in the shape of Pound, has made his peace with Neptune, his homecoming isn't quite what he had in mind. Just as Odysseus would wander off on further adventures after returning home to Ithaca, so the speaker of the canto has further worlds to conquer. There is still "some climbing" to be done toward the splendor of that light that points to a paradise beyond the speaker's present situation of confinement, both physical and poetic.
In that sense, the speaker's homecoming, like that of Odysseus, is only temporary. Nonetheless, with his mind "leaping like dolphins," the speaker is excited that the hardest part of his epic journey appears to be well and truly behind him.