If not, is there another way to make analog audio via USB work?
Without dtparam=audio=on you will get a no soundcard detected message when you ssh aplay -l
Also with dtparam=audio=on you will get the old type audio alsa options in kodi audio settings where you choose hdmi vs analog which where removed for some reason with LE9..
I am assuming that while analog audio on rpi is
card 0: ALSA [bcm2835 ALSA], device 0: bcm2835 ALSA [bcm2835 ALSA]
and hdmi audio is
card 0: ALSA [bcm2835 ALSA], device 1: bcm2835 IEC958/HDMI [bcm2835 IEC958/HDMI]
there is a big possibility that your device will be listed as card 1 device 0
card 1: Device [USB PnP Sound], device 0: USB
So in retroarch audio settings-audio device enter
and that should output the RA audio to your card