MPU6000 CS pin using I2C
When using the MPU6000 in I2C mode should CS be ground or VCC?

Consider the information you know:

In the datasheet it says (0=SPI mode) in the pin descriptions

Clearly, you would not want it to be tied to ground for I2C mode.
So the question then becomes, should it be floating or high?
The safe solution is to place a resistor footprint tying it high; you can then either install that component or not.
Most likely you want to tie it high through a 0-ohm resistor.
If you want your board to also support the related MPU6050, you probably want to have provisions for the bypass capacitor which that requires, as in that case pin 8 is actually a power supply.
Keep in mind also that the MPU-6000 is an old product not recommended for new designs.