Thanks to a lot of work from @pythoncoder, my old mpu9150 module now also works with the newer 9250 chip and is much better overall.
You can find it here:
https://github.com/micropython-IMU/micropython-mpu9x50
Note that we started a micropython-IMU organization. We hope that there we can collect drivers for all sorts of IMUs, barometers, as well as sensor fusion code. Basically all that's related to that. So if you hack on such a thing, join us!