At first I thought the same to leave it on 4.5 but my thoughts have changed now. Its pretty simple in the end to update to 9.2 and downgrade mset to 6.x. This is what you need to do.
1) Use sysupdater .3. Yes I use .3 as it was before that mess of the beta release that caused bricks and I rather just use what works previously. The older .3 works just fine as I did the update for a few of our consoles
2) Use 3DNUS to download the 6.x system settings. Use FBI to delete the 9.x system settings from nand and install the 6.x one.
Now you can use the mset to load rxtools. And on your sysnand you can now play retail carts if you choose that need higher than 4.5 and also you get theming on there as well. So the benefits are really good since you can use mset now.