Well, since you got 1 Post on this site and gave no details of your ZX9r...plus this is important...remember this you bought a ZX10R USED and who knows what problems it has after 4300miles and the abuse from the previous owner.
Now, as far as the zx9r giving your 10 a run for the money that doesn't count anymore. I came off the zx9r modified, full system, special carb upgrades and ran like a beast....but when I first got my 04 10R I only needed to open it up once to know I had something special and much faster than my 9r which at the time I thought I could take on Busas with my 9r
...with my 10R I know I can.
So, my advice to you is go get your bike fully checked out like compression checks, some dyno #s against other bikes the same day. If the bike checks out good it's most likely you don't realize the difference from your 9r with better lower gearing but make no mistake a 10R stock will eat your old 9r even with those great bolt-ons.(also if your in high elevation you may not feel much difference from the 9r to 10R)
Now, with that said try gearing your bike down 1 tooth in the front a 104mph is not needed for a bike and that may be why your a little miss guided between the 2 bikes if your Used 10R checks out to be good and at stock gearing....it may help for your riding style or the comparisons you have been doing so far.