What is the format specification for Avidyne R9 flight data?
According to section 12-4 of the Release 9 Pilot's Guide, data logs are saved as a simple .csv file that can imported into any spreadsheet software (like Microsoft Excel) for analysis.

There are many free tools that can covert Excel files to KML for Google Earth, ie: http://www.earthpoint.us/exceltokml.aspx