I am a tenant in a house for which a writ of possession was issued today. I had a lease purchase arrangement with the foreclosed owner, which of course is no good anymore. I was given ninety days. I live in Orlando Florida. Can filing chapter 13 automatically stay the writ? If so, for how long? Is there any other way to file a motion for a stay?

No, if the previous owner of the home that was being forclosed had filed bankruptcy it would have slowed the foreclosure.

But this is merely a eviction of a renter, and not for non payment, merely with legal notice as required by federal law.