user18846: I recently purchased the Arduino 9-Axes Motion Shield. I have two questions:
Q1. The official Arduino page says that the shield doesn't have any external power source and can only be powered up by stacking on top of an Arduino board. How can I use this shield with a Raspberry Pi?
Q2. A page here shows that it has support for the Ethernet Shield but doesn't mention WiFi shield anywhere. Does this mean that I cannot use my WiFi shield with it? I plan to stack the 9-axes shield on top of the WiFi shield which in turn is stacked over Arduino Uno.

user4143: 
Q1. The official Arduino page says that the shield doesn't have any external power source and can only be powered up by stacking on top of an Arduino board. How can I use this shield with a Raspberry Pi?

By providing the right power to the right pins.

Q2. A page here shows that it has support for the Ethernet Shield but doesn't mention WiFi shield anywhere. Does this mean that I cannot use my WiFi shield with it? I plan to stack the 9-axes shield on top of the WiFi shield which in turn is stacked over Arduino Uno.

No, it says it is compatible with the Arduino Ethernet which is not a shield, it is an Arduino.
What other shields you can use it with depends on what pins those other shields use.  Look at the schematics. Read the manuals. Do some leg-work.

18846: <p>I recently purchased the <a href="http://www.arduino.org/products/shields/5-arduino-shields/arduino-9-axes-motion-shield" rel="nofollow">Arduino 9-Axes Motion Shield</a>. I have two questions:</p>

<p>Q1. The official Arduino page says that the shield doesn't have any external power source and can only be powered up by stacking on top of an Arduino board. How can I use this shield with a Raspberry Pi?</p>

<p>Q2. A page <a href="http://www.mouser.in/new/arduino/arduino-9-axes/" rel="nofollow">here</a> shows that it has support for the Ethernet Shield but doesn't mention WiFi shield anywhere. Does this mean that I cannot use my WiFi shield with it? I plan to stack the 9-axes shield on top of the WiFi shield which in turn is stacked over Arduino Uno.</p>
 4143: <blockquote>
  <p>Q1. The official Arduino page says that the shield doesn't have any external power source and can only be powered up by stacking on top of an Arduino board. How can I use this shield with a Raspberry Pi?</p>
</blockquote>

<p>By providing the right power to the right pins.</p>

<blockquote>
  <p>Q2. A page here shows that it has support for the Ethernet Shield but doesn't mention WiFi shield anywhere. Does this mean that I cannot use my WiFi shield with it? I plan to stack the 9-axes shield on top of the WiFi shield which in turn is stacked over Arduino Uno.</p>
</blockquote>

<p>No, it says it is compatible with the <a href="https://www.arduino.cc/en/Main/ArduinoBoardEthernet" rel="nofollow"><em>Arduino Ethernet</em></a> which is not a shield, it is an Arduino.</p>

<p>What other shields you can use it with depends on what pins those other shields use.  Look at the schematics. Read the manuals. Do some leg-work.</p>
