I did the transmission fluid change once on my 09 V at 30k miles. I used the GM 88861800 fluid which was repackaged Dexron III ATF. There were a ton of threads on this back in 2010. GM moved to a newer Dexron IV ATF and that was specifically not allowed in the manuals transmissions. Some different additive or something would be bad for it. So they released that part number above. That is probably why the service manual and owner's manual have what seems like different text.
The change on the 09 V wasn't hard. You did have to start the engine during the procedure to get fluid into the cooler. That made me a bit nervous starting the car while on jack stands. But it didn't move any when I started it. I used a suction gun to fill which took a while and was a bit messy.