I know that in HG/SS you can get Ominous Wind on a Vulpix/Ninetales through move tutor. But if I was to bring one over to X/Y or OR/AS could I breed it and still get Ominous Wind? I know it's not listed as an Egg Move so I wasn't sure if it could be brought down for sure or not.
Unfortunately, if Ominous Wind is not an Egg Move for Vulpix then the only way to get another one would be to teach a second Vulpix Ominous Wind form the Move Tutor.
Sources: http://pokemondb.net/pokedex/vulpix and http://www.serebii.net/pokedex-xy/037.shtml
As you can see, Ominous Wind is listed under the "Transfer Only" section on both pages. Therefore Ominous Wind cannot be bred onto a baby Vulpix.