Tried with default theme: Yes

Tried with all other plugins disabled: Yes

In old version I could use <i class=”fab fa-youtube”></i> as Title in Arve Link open lightbox but new version seems to require actual text? 

Answered question

You did not provide enough information how you tried to put HTML into the title, and what the actual output it. I can not reproduce this, I can still use that HTML as a title attributes on a shortcode in 9.0. In my case it’s the italic test INSIDE here: https://nextgenthemes.com/test-page/ because I do not have fontawesome CSS in this side.

Ok I was using it without any text so just the code as title.

It’s not about the text, I just that to test if the HTML gets escaped or removed – it dosn’t.

At least it would surprise me very much if it works for you with text. Inside the tag. Can’t help you if I do not have a real clue what you are doing.