Darth Id said:
One way would be to reference her fate in the crawl to IX, which would fit into the in media res opening sequence of the original film… .

I hope they don’t do that. Because the triumphant John Williams music accompanying the crawl is not a right music tone to announce someone’s death, especially when that coincides with the actor’s death. If we are to be told Leia died between Episode VIII and IX, then it needs to be done in a subtle manner, with soft/mournful music, in a separate scene.

Perhaps, we can have Ben Solo/Kylo Ren visit Leia’s tomb/resting place in secret.
But no, Leia’s death should not be announced during the opening crawl!