You could continue using your gateway and 3ds files, or you could use cias, I only use cias but there's nothing stopping you using both
You would need to upgrade from 4.5 as homemenuhax relies on themes which 4.5 doesn't have
I can see why it's a lot of hassle, I didn't have emunand before and the idea of doing all this was a pain, but its worth it to me cos now it's done that's it forever
If you load up the gateway menu, you can do a NAND dump while on 4.5, then if you get to 9.2 and you don't link it you can flash the old nand via gateway again
Just make sure not to update last 9.2