Well, it should say which version it wants to install. To be absolutely certain, you could do it with wifi disabled I guess. I've noticed that downgrading seems to cause the nag. My 4.5 that's always been on 4.5 never gets the nag, just setting both Spotpass settings to "no" worked. My Zelda one got it immediately after downgrading. Even with me going out of range to change Spotpass settings, then updating to 4.5 using SMT IV. Turn on wifi, there it is. You can system format to kill it (what I ultimately did to eliminate whatever was causing it to go looking for the update), or try that thing where you power on with L+R+Up+A and cancel the update. If it's on SysNAND. If it's on EmuNAND, the very act of going to 9.4 might get rid of it.
Thank you so much!