TBH, in the world of amplifiers, that is a negligible difference in power between the 2 models.
We've established that your Kappa's are basically a 4 ohm speaker, so we are not interested in the 8 ohm spec of 75 wpc. The speakers will be drawing higher current from the amp which relates to the 4 ohm spec. So the 9010 is rated at 60wpc and the 9050 is 65wpc, they are basically the same power, even at 8 ohms. The difference between them is extra features on the 9050.
We've established that your Kappa's are basically a 4 ohm speaker, so we are not interested in the 8 ohm spec of 75 wpc. The speakers will be drawing higher current from the amp which relates to the 4 ohm spec. So the 9010 is rated at 60wpc and the 9050 is 65wpc, they are basically the same power, even at 8 ohms. The difference between them is extra features on the 9050.