The Wixel cannot be powered directly by a standard 9V Battery. The maximum input voltage is 6.5V.
Though the Micro Maestro has a 5V output on the board and can use input power sources up to 16V, it is only capable of providing a small amount of current (<20mA) to external devices and will not be adequate to run Wixel.
You might consider using one of our 5V regulators to supply power to the Wixel and the Micro Maestro. It is likely that using one of these regulators would also extend the battery life of your project.
Finally, if you have not already tested your communication from the Wixel to the Maestro, you should keep in mind that you might need a logic level shifter since the 3.3V signals from the Wixel might not be recognized as logical highs on the 5V Maestro. If you want to send feedback to the Wixel from the Maestro, you will need the logic level shifter as the Wixel will not tolerate 5V signals.