Hi,
I replaced a sensor in December using this part, it works just fine and for £12 delivered.
https://www.ebay.co.uk/itm/VOLVO-XC9...72.m2749.l2649
Mine is also a 2006 (06) XC90 D5 185bhp.
I found getting the right part quite difficult for a 06MY, most sites quote the 2006 as 163BHP and 2007 (facelift) as 185BHP yet the 185 was introduced pre facelift.
I got the part number from VIDA and matched it that way.
Hope this helps.
Wish I had known about not removing the bumper. It was not too bad but the clips just behind the wheel arch were so tight..... Much easier second time (don't ask).