That line is most definitely an allusion and not personifcation.
Personification is when you are talking about an inanimate object and you give it human characteristics. For example, you could say that the line about the planet "swimming" is personification because planets don't swim.
But the line you mention is allusion. It is referring to someone (in this case, the poet Homer) that everyone who reads the poem is likely to have heard of. Homer was a very famous Greek poet and, in the time that Keats was writing, any educated person would have known who he was.