Answer
9 axis MotionFusion combines gyroscope, accelerometer, and magnetometer sensor data. The resulting angular frame is relative to both gravity (down) and north. 9 axis MotionFusion is not available in Embedded MotionApps Platform at this time.
The advantages of 9 axis MotionFusion over 6 axis MotionFusion are that 9 axis MotionFusion results are usable for navigation and other applications which require information about the angle relative to north. It also eliminates any heading drift which may be present in a 6 axis MotionFusion solution.