Seeing both a Jedi and a Sith simultaneously believe they’d find redemption through Vader was awesome, and was yet another example of “things I hate about the PT that are mostly alright in this context”.
I didn’t think they were talking about Vader.
Likely it was kept intentionally ambiguous.
There’s nothing really ambiguous about it.
Maul: Oh, you have a purpose here. Perhaps you are…protecting something? No…protecting someone.
Maul: Tell me…is it the Chosen One?
Kenobi: He is.
Maul: He. Will. Avenge us…