While its possible (likely) that there's a RTC in the ME9210, its not really usable - there's no way of adding a backup battery.
The RTC in the Connectcore 9P, which uses the 9215 processor, is accessible - however I found that it took quite a high backup current in the absence of power, so now use an external one instead.
There's a reasonable amount of info in the Net+OS HTML help file.