Serge, every owners manual for every vehicle with a manual shift will give you rediculously low rpm and mph shift points. Optimal gas mileage is used as the excuse fairly often. My RX-7's manual tells me to shift at 2500 rpms, when the car doesn't even start to make any power until 4k or so. It would take me 30 seconds to hit 60mph if I shifted at 2500 rpms.
The 9'r is solid as a rock. Keep the oil changed and the air filter clean, and shift it whenever the hell you want. It's just like everything Honda.
If you're not sure, take a poll here and see how many of us have had engine failures due to running the hell out of our bikes. Not many, I promise you.