There's not much you can do to salvage the ruined decals, but you can probably rescue the remaining ones.
For older or defective decal sheets there are two generally useful methods. First, spray the sheet with some clear gloss finish. It will help hold them together. The other option is to buy a product like Microscale's Liquid Decal Film. You brush this over the decal and it forms a new film over the top.
For both methods, you now have to cut the decal very close to the image, without leaving much of the clear film around the edge. I use a pair of curved nail scissors for this.
I've rescued a lot of decals with the Microscale product. It is very thin and usually becomes invisible when you're done.
2009 is not very old. I've used ten year old decals with no problem. I've read that it's more a manufacturing defect than old decals, but humidity can affect them too.
Good luck.