I would never use a plural for "poetry". I can't think of any circumstance under which "poetry" would need a plural. Finding Google hits doesn't really prove anything except that not everyone agrees with me! But from looking at the first page of hits when I googled "poetries", it is simple misuse. "Poetry" has no plural in most of the main dictionaries (OED, Cambridge, Websters, Mirriam-Websters, etc.)

The idiot also known as Capfka ...