Is it compatible with A9LH? When Yes, how to switch?
Only the normal .3dsx version of ctrbootmanager is compatible with 3dsx homebrew, not ctrbootmanager9 or any other a9lh version.
This is, because .3dsx homebrew is designed to use the enviroment the firmware creates for the arm11 processor, shile a9lh homebrew payloads are running on the arm9processor, and before anything got initilaysed by the firmware.
To boot easily hombrew simply use this, to boot the homebrew launcher from the home menu:
https://github.com/yellows8/hblauncher_loader
Also, if oyu enable the logging, bootctr9 should show a error message. On the next release screen init will be forced, if any critical error is occurring.