you will still get exp and EVs in double battles, however since your game is x and y are you not able to do any double battles in the wild except for the resturants, and the battle maison. in the battle maison are the levels set, and you are not able to get exp. points, nor EVs. the resturants will cost money to battle in. my tip if you dont have much money is to use a Pokemon with sweet scents and use it in tall grass, 5 Pokemons (horde) will appear and you will get EVs and exp.points from each of these.
use a macho brace and pokerus to get 4X the EVs, X5 in hordes=much EVs
hope I helped :D
MASSIVE EDiT: after trying it myself, I noticed you dont get EVs by knocking out partner in diuble battles. So sorry D: