There are no games that require firmware 9.0 so there is no reason to update yet.
I mean there is nothing that will ever 100% guarantee a ban just as much as there is nothing that has a 0% chance of a ban.
Unfortunately, ReiNX 2.4 does not support firmware versions below 6.2
I think it is saying updates are available for your .XCI files
Theoretically, you cannot burn fuses with emuMMC. The main purpose of emuMMC is to run a firmware higher than your sysMMC. AutoRCM only prevents fuses from being burnt when applied to sysMMC.
There is DevMenu but that is a copyrighted application that we cannot link here even via PM.
No, setup emuMMC before updating your firmware.
You can still enter Maintenance Mode even on emuMMC. Simply hold both volume buttons when booting emuMMC. Entering Maintenance Mode will automatically clear out any pending system updates.
https://github.com/exelix11/SwitchThemeInjector
No one has been for using AutoRCM and Stock Mode, including myself, so I would say you do not need to disable AutoRCM and can boot Stock to play your game online.