Yes, it is supported. I have the settings in the admin area.

Hello
It is a new router and very popular. Therefore, I strongly assume that it supports it. I know this is the case with the popular Fritzboxes, but you may still need to set up the box for IPTV transmission. With the Fritzbox, navigate from the main menu to the sub-item "WLAN" -> "Radio channel" -> "Further settings" -> there you put a tick in the option "Optimise WLAN transmission for live TV". I think it is similar for the ASUS RT-AC88U router. IGMP snooping is a frequently extended option on today's routers.
I hope I was able to help you...