The modern dual-camera devices don't allow user control the way they use the lenses. I explained the situation also in an answer to Capturing a photo from only one lens, in dual-camera phones?. These devices have different cameras, e.g. color and mono (in case of Huawei P9), so reconstruction of stereo image would be difficult if not impossible even if you somehow get control of the two sensors.
On the other hand, the HTC Evo 3D phone comes with SDK that lets you do exactly this: work with the stereo picture.
