I think it is the opposite - the 9 has more midrange. I suspect AM's 808 mod is very comparable to an 808 RI, though people will argue that a vintage 808 sounds better than a modern 808 (same with the 9's), and this is reflected in the used price sale. It really comes down to personal preference, for a recently made pedal (after original TS's), I would go with his Silver option, which I have two of. A few TS9 geeks like myself have urged me to try a vintage original so I might pick one up. The extra mids in the 9 might make it more effective for lead respectively, which is what I would use for lead and a silver/808 for a cleaner one.
They're the same pedal, built on the same circuitboard. The TS-9 is a TS-808 with 2 different resistor values in the output secition that make it a bit brighter and slightly less smooth. I wouldn't get hung up on the differences. I cringe whenever I read on forums people saying things like they sound "worlds apart" or whatever other cliche people tend to use.
A greater tonal difference in these circuits is symmetrical clipping (tubescreamer) versus asymmetric (Boss SD-1; Fulldrive). I personally like my orange FD2 better than the 82 TS-9 I had before it, and reckon it's the asymmetric clipping I prefer.