People A9lH/B9S is not the issue here. It's your CFW/system, or combination of the two. If you installed CFW for the first time recently, did you have an hiccups during the process? What guide did you use? What SD card do you have? How long have you had your console?
If you installed CFW a while ago do you remember how? Have you made any changes to system titles? Edited the Home Menu? Installed patched CIA titles like AGB/TWL firm? Do you use save editors? How do you download your games? Do you wait for things to load properly before loading something else?
Do you see where I'm going with this? All of those questions 100% matter when you're troubleshooting stuff, and all of it can affect the way your system works or doesn't. Certain things will not work under certain conditions (conflicting software) and instances can normally stress the console enough to say "Screw you!" and crash. From the way that B9S/A9lH work, if your console boots at all it's not an entrypoint issue period. Even though it wasn't crashing on A9LH, doesn't mean it wasn't giving you the same issue without an exception crash. All B9S versions of luma (.FIRMs) have changed the way Luma works in the system entirely so it's 100% possible this was happening before, but Luma didn't have the info/ability to let you know there was a problem.
If you buy a stock system on 11.3, install B9S and Luma 8.1 flawlessly you won't have these random crash issues. Your problem seems to be centered around specific titles that crash only for you, but it's not consistent for every use with your setup. Common sense says it's something to do with your personal unit and what you've done with it prior to this.
I would also like to point out that electronics don't last forever. The O3DS was originally released on 2/26/2011, over 6 years ago. Electronics have a half-life of 5 years give or take (plenty last longer but after 5 years you can expect hardware to malfunction). So depending on how old your console is there is a good chance your VRAM is just failing, resulting in crashes.