The problem also did not occur on my S8 Ultra. I also tested with the companion app and encountered no errors. So I'm at a loss to explain what you are seeing. I believe the error is occurring while MobileSheets is reading data out of the .msb file and it tries to read out a string (such as a song title, file path, etc), and the data does not represent a valid string, so Google's reader object throws the exception you are seeing. I do not know why your device is encountering the error but my devices are not. It may have to due with the handling of the Japanese characters on your device. Can you please provide a link to a description of the device you are using? I'm not familiar with the C9.
Mike
Mike