So to clear a few things up:
1.
The OP Luma build will not work on the current highest firmware version is it is only 9.0. Do
NOT use this boot.firm from the OP.
2.
BootNTR is a standalone CIA that has the best backwards compatibility for all old
.plg plugins.
3.
Badda recompiled the OP Luma build to include 9.1. This works with some old
.plg plugins but not all. Given the more limited plugin support and the fact that the OP has created a new framework since: this build should be considered deprecated.
Use BootNTR instead, it has much better coverage.
4. Nanquitas, the OP and creator of everything NTR related (by the looks of it) made a new framework for
.3gx plugins.
This 9.1 Luma build works exclusively with
.3gx plugins.
5. There are not many
.3gx plugins around but latest
Mario Kart 7 - Custom Track Grand Prix 7 (CTGP-7) uses this new
.3gx framework and therefore needs the above Luma build.
6. Nanquitas also created a
"blank" .3gx plugin that has a hex editor, AR cheats and New 3DS button support (C-Stick, ZR). This can be used for
any game (rename & place at sd:/luma/plugins/default.3gx) and this is much better than any old AR
.plg plugin.
7.
All hail Nanquitas!
8. I have compiled a custom Luma 9.1 build that merges Nanquitas' .3gx plugin loader with Sono's CTR_Redshift, plus a few minor tweaks for personal use. You can find it in my sig and I aim to keep it up-to-date with any main Luma changes, Nanquitas .3gx plugin loader changes and potentially basic new feature suggestions.
tldr
BootNTR for .plg plugins
This Luma for .3gx plugins