Odyssey roughly translates to "The story of Odysseus", so yes, the name existed before Homer's story. The semantic connection of odyssey and a long, dangerous and arduous journey came way after that.
The Odyssey was called Odysseia. The suffix -eia is an abstract noun suffix, so it's sort of like a titular case for the name. Following the same logic, it would be Homereia and thus Homerey.
Odyssey roughly translates to "The story of Odysseus", so yes, the name existed before Homer's story. The semantic connection of odyssey and a long, dangerous and arduous journey came way after that.
Does that mean a story about Homer would be a Homey?
The Odyssey was called Odysseia. The suffix -eia is an abstract noun suffix, so it's sort of like a titular case for the name. Following the same logic, it would be Homereia and thus Homerey.