Incorrect check the following:
Power rating is 130W at 6 ohms - matching specs of NR609 / RC360 (the NR509 is rated at 110W at 6 ohms)
Upscaling shows Marvel Qdeo 4k (again an obvious feature on the NR609 / RC360 not found on the NR509)
Confirm what I am saying here:
Check the specs on the NR609 and you will see they are identical to the receiver on the S7400 (which is the RC360). So the S7400 comes with the RC360 and the S7409 with the NR609. Which in case you don't know are essentially the same.
Check for specs for yourself if you want to verify what I am saying:
Here is the NR609:
Here is the NR509:
Unless of course Onkyo is lying about the specs on the S7400 receiver then you may be correct. I can tell you that the receiver sounded every bit as good as my SR608 that I have in my home theater!