I think 'base' 2009 C6s were fitted with Goodyear Eagle F1 run-flats; the Black Book isn't very specific on this, altho' it does record that 2009 ZR1s left
Bowling green with Michelin Pilot Sport 2 tyres.
Mike B: I found when I wanted G'year F1 run-flats a few years ago, they were temporarily unavailable; apparently they were (still are?) made in
batches and there was an unspecified delivery period. I wasn't prepared to wait so bought some Michelin Pilot Sport 'ZP' ('Zero Pressure', i.e. run-
flats) for the front on my '07. (I had previously managed to get G'years for the rear, so am currently running Mich. on the front and G'year on the rear;
doesn't seem to have any negative effects - well, not at road speeds, anyway).
As Norm says, you can't really go wrong if you stick with well-regarded makes of rubber such as Goodyear, Michelin, Pirelli, Continental.....
I wouldn't scrimp on tyre quality on your '09.
J.C. (1911)