You can make legit .cias from any game purchased through the eShop with FunkyCIA, but that .cia will only work on your specific console (and possibly NNID too.)
You can buy stuff from the eShop on emunand though and make it a cia with FunkyCIA, and that should install fine on your sysnand and play normally (of course unless it's a 9.6+ encryption game and you are on 9.2 sysnand.)
But from a piracy point of view there isn't much appeal in doing that