In the FAQ section under "Which input/output interfaces does Vuo support?" it mentions QuickTime video capture being supported around v0.5.9. Does that mean any UVC webcam? ... such as the Logitech C910? ;)
The goal for that release is that if you can use an video input device with Quartz Composer's built-in "Video Input" patch or with QuickTime Player's "File > New Movie Recording" feature, then you should be able to use it in Vuo.
Since the Logitech C910 is UVC-compliant and since Mac OS X includes a QuickTime wrapper for UVC, I'd expect it to work. We'll know more once we start implementing it in a couple months. :^]
Later on we're planning to implement native UVC support (bypassing QuickTime), to allow for more precise control over UVC cameras (e.g., setting exposure lock) which isn't possible via the QuickTime UVC wrapper.