Using A9lh is recommend, since it enables CFWs like Luma for example to enable firm protection and other stuff. The reason why homebrew and non-legit CIAs tend to break after a system update on consoles without A9lh is because certain things get patched during the update. With the firm protection these things are - as the name implies - protected and the patch(es) that usually break things can either be disabled or circumvented in some other way by the CFW of your choice.
TL;DR
If you would like to have an up-to-date system with non-legit CIAs installed and working without a future system update breaking anything, go for a9lh and a CFW of your choice (with Luma being the most used on). Once you installed A9lh and a CFW, it's a matter of turning on the 3ds, using FBI or Freeshop to install some games without worrying about anything else.