It’s hard to imagine a need to include Hayden in ROTJ, barring IX explicitly stating, “Every Force ghost has exactly one appearance and this is Anakin’s.”
I’d like to see a Force ghost appear two ways in IX, such as Luke appearing old and young either close together or to two different people.
Maybe he appears to Rey, who asks, “Are you an angel?”
“I’m a person and my name is Anakin.”