Wonderful piece. I like the parallels you've brought up with Sam and Gadriel/Gadreel (still not sure of the spelling). It would be interesting if they bring up something like this in the show, although with their track record of showing us Sam's POV (close to zero!), it's not likely to happen :S

But this made me realize that the concept of S9 itself is... something I could deal with, if the execution weren't so terrible.

Sorry for the strange comment, but me and S9-era fic (or just about any canon-era fic since S7, really) don't get along very well.