OK.
yes, the 9k ish or there abouts is what to expect when the saw is cutting. But dont mess with your H adjustment to get that when the saw is cutting, your just chasing your tail if you do.
Far too many variables to use that as help for tuning, ie how long is the bar, what type of chain, what type of grind, what type of wood, how thick is the wood, you see, far too many variables.
No, dont read wot rpm with the bar buried, wide open throttle reading is given with no load.
just set the chain to correct tension, warm up saw, then go wot to get a reading, ie dont pee rev it for any longer than you have to.
What your aiming to do is to set the max rpm no load to safe limits, the richness of the h setting is in effect an rpm limiter if you dont have a limited coil.
What the 9k ish rpm amount is saying thats where it gives its best torque for cutting, those numbers are just marketing value really, and not helpful for correctly setting the max unloaded rpm.
Now when you have a limited coil, ie a coil that limits the max rpm, you can lean out the H and the coil will limit the rpm, but your going too lean, and risk damaging the saw.
If you didnt have a limited coil, the saw would soar up to 15k or more depending on type etc, and thats not only an overspeed, but its too lean to provide a protective oil coating and cooling at that setting.
Most saws with limited coils have the sequence of richening up the H till its blubbering and 4 stroking below the limited coil speed, then turn it in leaner till it reaches coil limited speed.
ie
lets say the coil is limited at 13000rpm, so you adjust the H side and richen it up till your reading 12500ish, so the saw is now limited by the richness, not the coil, then lean out till your at 12950 ish + - 500 rpm, and you have set your rich limit, again, thats an example of a possible sequence for setting up a saw on a limited coil so your not running it too lean.
Best to find the correct procedure for your saw and follow that.
hope that makes sence.
here is a vid that shows an ms460 being tuned, it shows what rich, 4 stroking sounds like, and being too lean.