The SDHC card rating of "Class 2" means the card is rated to reliably sustain a speed of 2MB per second when writing data to the card.
Other flash memory card speeds are stated in terms of "X," where X = 150,000 Bytes per second. For example, the Kingston Elite Pro Compactflash card used by a lot of recordists is rated at 45X. This calculates to mean that the Elite Pro can write data at (150,000 * 45) = 6.75 MB/second.
In an audio recorder, the volume of data transferred per second from recorder to flash card is not very high. For example, if you record 2 channels at 24/96, then you're creating a data stream of 0.576 MB/second, considerably less than 1 MB/second.
So I'm thinking a card rated "Class 2" easily will keep up with a recorder set for 24/96 digitization.
The R-09's top digitizing rate is 24/48, half that of 24/96, so the "Class 2" card should have no problems.
Flintstone