No S9s are so insignificant that's not a good defense against a situation like that from a hashrate standpoint. Though it would be interesting from a legal standpoint as mass noncompliance like that would make enforcement at a larger scale more difficult. It would also mean more people willing to sue the feds.

The best defense against a state actor messing with miners is geographic distribution of hashrate. Fortunately it's growing more distributed and will continue to do so.

I think plebs can mine at home if they're also taking advantage of the heat produced by the miners. Any instances where space or water heat are produced by electricity are opportunities to produce that heat with a miner and stack a little corn on the side. This only works for folks who are willing to get their hands dirty.