Based on the answers, the Sony HX9V is the better fit if you want to start in auto mode but grow into more control later. The key reason is that its mode dial includes PSAM modes (Program, Shutter priority, Aperture priority, and Manual), while the Nikon S9100 is described as offering mostly scene and automated modes. If learning exposure is important, PSAM gives you much more flexibility.

The trade-off mentioned is image processing: one answer raises concerns about Sony superzooms using strong noise reduction that can make images look blurred, especially at higher resolutions. The Sony also adds GPS/compass, which may or may not matter to you.

One responder also suggests reconsidering whether you need an ultrazoom at all. If you don't, a model with a better lens and stronger manual controls may be a better learning camera.

So between these two, choose the Sony HX9V for ease now plus manual learning later. But if image quality and exposure control matter more than extreme zoom, it may be worth looking at a less zoom-focused compact instead.