Danger is really pretty low. Accidental hit could easily disable the plant from producing power, but with the amount of redundancy and containment around the reactor itself you'd almost have to deliberately attack the plant to cause any widespread contamination hazard. Beyond that, the hazard is primarily to local Ukrainian territory and Russia, so both sides have a pretty strong motivation to be careful.
The risk to Europe is minimal. And the statement that this would be worse than Chernobyl and Fukishima put together is complete and pure BS.