I recently sold my M9 here and have a few remaining accessories for the system.
1.) One battery, M8 model (serial 14464) - functions as intended. - Price: 100 USD net to me, shipped Free CONUS.
2.) Really Right Stuff - BM9-B Bottom Plate, fits dovetail arcaswiss type QR heads. - Price: 50 USD net to me, shipped Free CONUS.