In the FAQ in the "skylands" section (https://github.com/Multiverse/Multiverse-Core/wiki/FAQ#wiki-skyland) it states: So I guess, it doesn't have a feature like that built-in..
for creative try /mv modify set gamemode CREATIVE if you have worldguard /region flag __global__ game-mode CREATIVE
I think you can just set multiple game rules for each world, or atleast that worked for me... I just do " /gamerule doDaylightCycle false " and it normaly does not effect the other worlds. as for it being always creative, it is best you get a plugin called " GameModeChanger ", in the config you just add a world name under the GameMode, as if you are doing permissions, such as: creative: - world1 - creative_world1 - other_world would make it creative in all 3 worlds by default.