@Newbie_from_NJ
I too have an LG C9 and N2.
I initially had the N2 connected to the TV then used eARC to my amp for sound, I found this worked well except for on UHD remuxes with Atmos or DTS HD MA/X soundtracks where a delay was introduced between picture and sound.
Connecting the N2 directly to my amp cured this problem.
With your current amp this shouldn't be a problem as it doesn't look to be eARC compatible so only DD+ and DTS would be passed through to it.
If you want a solution to get the higher sound formats something like a HD Fury AVR Key would solve this, its an expensive solution but not as expensive as buying a new AVR.
I can't comment on the Shields Netflix and Amazon apps as I don't have a Shield, but the C9's in built apps are excellent, Dolby Vision and HDR on compatible films and shows, Atmos sound where available without the above mentioned problem via eARC, I haven't tried either on the N2 as I prefer UHD where available than the current 1080P limit on the Kodi addons.
An LG C9 and Odroid N2 is a great combo imho, I'm certainly glad I invested in both