Boy, you sound totally confused. Amps never have any inputs but preamp inputs, they are not designed to be used with audio playback sources, just preamps or receiver's with preamp outputs.
Second, if you want to watch blurays or DVDs, you have to use a player that can play that media and connect it to the preamp or receiver with either a HDMI cable or component cables.
Third, the Onkyo TX-NR609 and Pioneer VSX-921 have nothing to do with a bluray players performance. You need to find a review for the Bluray player you intend to use with those receivers.
Forth, as I said above, to play Blurays, you must use a player designed to play that media and either use the HDMI output or the component video cable outputs. The USB input on the Bluray players can be used to play a flashdrive with photos and music and some players offer video playback from a flashdrive from SD or even HD video files depending on the Bluray player.The USB port is not a video output for Bluray playback though.
Honestly, seeing your very confused about home theater components in general, you may be better off with an all in one system where the main control module is your receiver and Bluray player and uses speakers and a subwoofer designed for it. They are usually pretty cheap and Best Buy, HH Greg, Walmart and the like carry many different makes and models.
Good luck in getting set up.