Thank you for the correction about the Zumo version. The 5V regulator on the Zumo 32U4 can provide a little over an amp of current, but some of that is used by the logic on the robot. It would probably be fine for powering your Raspberry Pi if it only draws around 1A. You might check out this forum thread where someone asked about powering a Raspberry Pi from the 5V out of a Zumo 32U4.
-Derrill