GMPermissions is a simple PocketMine plugin that adds permissions to limit access to gamemode commands.
PERMISSIONS:
gmchange.others (allows a player to change other players' gamemode
gmchange.spectator (allows a player to use /gamemode spectator)
gmchange.creative (allows a player to be given Creative mode)
gmchange.nogm (allows a player to use the /nogm command)
Give the gmchange.nogm permission to allow players to use the /nogm command, which prevents anyone from changing your gamemode
Use the normal pocketmine.command.gamemode permission to give players the ability to change their own gamemode.
Give the gmchange.others permission to allow players to change anyone's gamemode
Give the gmchange.spectator permission to allow players to use spectator mode
Give the gmchange.creative permission to allow players to be be given creative mode (when 'restrictcmode' option is true)