Actually DevMenu might be able to do it too, hadn't thought of that.
Since you are replacing an older version with a newer one it might not complain too much that a higher version already exists.
IIRC though DevMenu doesn't really deal with system titles, can't be used to remove system titles, so that's why people use FBI if they need to replace a system title. Usually with an older version though, maybe replacing an older version with a newer one won't throw any errors.
Also you are using an european console? You'd need 0004001000022000.cia in the 9.0.0-20E update pack then (9.1.0-20E and 9.2.0-20E would work too as they all have the same system settings app.)
I assumed you were using a north american one since your flag said USA, I guess maybe you could also just have left it as default location since it defaults to USA. Either way.
I believe to restore nand backup with GW Launcher you would have to hold Up on the Downgrade option or something. I'd just recommend using Decrypt9 though because it directly has an option to restore nand backup to sysnand.