The other Volvos with paddle shifters are based only on the P3 and SPA platforms, the XC90 is a P2 platform car.
My guess would be that it will be difficult to retrofit functional paddle shifters.
But don't let my guess to stop you trying. [emoji6]

 

Someone did it to an R, which is also P2, which means it is possible, but that's been quite a while ago and I believe it was VERY expensive.

 

Hmm....got it. Thanks!

 

this might help
http://www.benzworld.org/forums/r170-slk-class/1604054-paddle-shifters-non-paddle-cars-diy.html

 

Nice link snivac! That's actually the car and message board I came from prior to the XC90. Talk about a different world from petite roadster to a 5,000 lb. Moose.

 

In theory you could do a paddle shifter setup if you associate the steering wheel paddle electric switches to the transmission manual +/- switches. Then you need to either leave the shifter knob in the manual slot after putting it in "D" or set up another associated switch to put it electrically in the manual mode while in "D".

No clue how you would implement a paddle onto your existing P2 Volvo wheel, maybe use another manufacturer's wheel and re-wire the airbag?

Seems like a lot of work for something the car was never designed to natively do.

 

Here's the one time it's been done that I know of:

http://forums.swedespeed.com/showthread.php?134679-My-new-B-Line-MotorSports-MOD!