I remember seeing an explanation of Toki's prophecy somewhere on the internet and imo it makes a lot of sense.
You are the moon unaware of the dawn. May your purpose be fulfilled and cast nine shadows on the night woven of 20 years... And you shall know the brilliance of the dawn
Basically, Toki was talking to Oden when she was saying it. The Moon is Oden (The name Kozuki contains the kanji for "light" (光) and "moon" (月).
May your purpose be fulfilled and cast nine shadows on the night woven of 20 years = Oden's purpose was to sacrifice himself to let the Scabbards escape 20 years into the future. Scabbards are the nine shadows
And you shall know the brilliance of the Dawn: this part is obviously about the Dawn of the World which Luffy is supposed to bring. Scabbards, the 9 shadows, allied with Luffy to strike down Kaido. Opening the borders of Wano is somehow tied to the Dawn of the World