Is a 9 axis shield pin-out diagram or description available?
What are the TWI, OUT 5 & 6 and IN 2 & 3 pins used for?
IN2,3 : probably lines to pins 2 and 3 (with Ucc and GND added) Suitable for external interrupts
OUT 5,6 : pins 5 and 6 ...smart.. they are PWM capable
Two Wire Interface, TWI (I2C) pins A4,A5
I wouldn't spend my money on this one.. (plug-in shields can restrict flexibility)
The sensor can be found as BNO055
That is an orientation sensor, not a position sensor.
I would not be surprised if there is some documentation associated with the sensor. Have you looked at it?