Homer, the poet, shows us everything that happens in the Odyssey. The narration appears to be in the third person unless you consider Homer’s invocation to the Muse in Book I in which he uses personal pronouns and references himself telling the story. Of course, you could write this off as a standard introduction, not as part of the poem itself, in which case Third Person Omniscient is the label you want. Either way, practically speaking, the poem reads like a third person tale, usually vocalized through Odysseus or Telemachos, because Homer is not a character and does not take part in the action.
In Books IX – XII, Odysseus becomes the narrator and tells the story in the first person, which allows us greater insight into the psychology of his character. We get to see how he views his experiences, whether or not he has learned from them (for instance, does he tell his stories with a sense of reflection and wisdom?), and whether he still suffers from certain key flaws (does he tell his story with an excessive measure of pride?). And importantly, this narrative tactic works for Homer structurally; it allows him to deliver the story of the Odyssey out of its proper chronological order; he gets to jump right in to the middle of the action when the epic begins.