You really need to expand your horizons beyond lunatic-fringe, conspiracy-Christian wacko sites. Neither Hynek (who has been dead 38 years) nor Vallee (who is now 84) would ascribe the UFO phenomena to anything like the "demonic" in the lunatic-fringe, conspiracy-Christian wacko sense in which you are using the term. I have seen lunatic-fringe, conspiracy-Christian wacko sites where what both Hynek and Vallee actually said has been taken completely out of context to support the wacko perspective. You have obviously seen them as well.
The evolution of Hynek's views is explained quite well in the Wikipedia entry:
J. Allen Hynek - Wikipedia.
Precisely as I suggested, both Vallee and Hynek recognized that the UFO phenomena are too mysterious and multi-faceted to be explained in terms of nuts-and-bolts alien craft. Both noted the affinity between the UFO phenomena and other phenomena (including Marian apparitions and folklore tales of "little people"), as well as the non-material and even "psychic" aspects. They both speculated about other dimensions and higher realities - but not "demonic" in any sense close the way you are using the term. Rather, they would be more likely to explain the demonic in terms of the UFO phenomena, not vice-versa.
YOU SIMPLY DON'T KNOW WHAT YOU ARE TALKING ABOUT. If it makes you happy to ascribe to lunatic-fringe, conspiracy-Christian wacko thinking about UFOs, be my guest. Your references to CERN should be sufficient to tell anyone this side of sanity that this is lunatic-fringe, conspiracy-Christian wacko stuff.