The Scirra GooglePlay plugin is only for web. Not for mobile. (I know, it makes it pretty useless)
The Cocoon.io plugin works fine with mobile. (but they do not have the fetch leaderboard built in. They just have the Show leaderboard action, which open the leaderboard outside the game. which is ugly as hell)
So unfortunately there are no perfect solution, and no fully functioning plugin which got the desired features