Older S9 firmware recorded in a proprietary format called DVR. The newer S9 firmware will record standard TS (Transport Stream) files. DVR files can be "unwrapped" and the TS file extracted using utilities such as the Ariva TS Tool or Cypheros TS Doctor.
The OP probably has the older S9 firmware that records in DVR format on his S9, which would probably explain why the S10 won't play his S9 recordings. Best thing to do would be to upgrade the S9 to new firmware and convert the old DVR format recordings to TS using Ariva TS Tool or Cypheros TS Doctor.