Sincraft, so after calibrating, your in E6b, and as you noted your now 9 mph faster than calibrated.
That means you bombs are going to be going faster, will hit ahead of the crosshairs.
Instead of recalibrating, just pull the rpm's down on your engines. Or if its over 20mph, cut throttle.
Keeping an eye on upcoming targets "Balance" the 2 speeds until they are the same. As you hit the keypad - cutting rpms, actuall speed will start dropping. This does take some practice, but normally 3 - 6 keypresses down on RPM will pull that speed down 10 mph in 10 -15 seconds. Once you get close, you'll have to add a couple of clicks up to to keep from going right past your target speed.
Try practicing this in the TA, Calibrate, get the speed, then using rpm make the plane speed STAY at that speed.
Don't sweat time or target. Just concentrate on getting the speed within 1 mph, and keep it there.
Once you have learned what that takes, you'll find its much faster to just correct a small speed error rather than recalibrate, and much much more accurate.
If you can't hold it perfectly stable don't sweat it, remember, you just need to be in the target speed, over the target, for 2 or 3 seconds. So as long as your ready to drop the bombs, and your speeds are going to match as your doing so, or within 1 -2 mph as you do so, you will hit the target.
Everything else is practice and confidence, and will fall right into line.