Hey, only if You clean the window with alcohol and let it dry properly, the suction rubber cup will hold properly. The click mechanism connecting the holder with the base is not the worlds greatest, but if you will not be unlocking it too often it will do the job. The combo otherwise does the job holding the N9 very well.
I've been looking at different alternatives and found that, in spite of being a little more expensive, the Kenu Airframe is a more portable and discrete (and sexy) car holder (and has very good reviews.. it will also fit the N9), so I will go for it.