According to the TX-NR609 manual page 62,
Only analog input sources are output from the ZONE 2 LINEYou need to connect PC, GAME and CBL/SAT channels analog audio outputs to the TX-NR609 via RCA (Red and white) cables to make it work.
OUT L/R jacks and ZONE 2 L/R terminals. Digital input
sources are not output. If no sound is heard when an input source is selected, verify that the source is connected to an analog input.