The story of Russians digging holes and getting radiation poisoning was propaganda, just like Ghost of Kiev. The levels of radiation in the soil are not high enough to cause radiation poisoning, except for very few hotspots that they'd have to go looking for. It's mostly alpha radiation left which is dangerous only if radioactive particles are inhaled.
I'm more inclined to believe the IAEA. Also,
>They concluded that the radiation levels where the soldiers camped were three times what the IAEA reported
Three times more is not much when talking about radiation. Flying in a plane exposes you to about that much more radiation compared with being on the ground at sea level.