Xehanort didn't exist at this time. Master Xehanort, yes. But destinykh was referring to Xehanort, aka the pretty one. Xehanort as we know him has no past beyond about a year or two before te first Kingdom Hearts started, when he showed up unconscious and without memories in Radiant Garden as stated in the Secret Ansem Reports.
He showed up right after BBS ended. o.o;; Not a year or two before KH1 began. Since after he and the apprentices banished AtW and became Heartless/Nobodies, Maleficent took over Radiant Garden. And Leon said that happened nine years before KH1.