a god that can create an entire universe in seven days just to lavish attention and affection upon the peoples of a certain small globe certainly wouldn't cavil at revealing his existence to a heretical farmer through golden plates that require a magical gem to translate

Fixed that for you.

Surely, the repentant Xenu - who ordered the genocide of countless billions of intelligent beings - could, if he chose, decide to reveal the true nature of their sufferings to the denizens of the planet Earth through the writings of a science-fiction author of questionable talent. And clearly the unbelievable nature of his claims only lend them greater authority, because who would ever make up something so ridiculous in an effort to get people to believe?