Greedy Algorithm $1$: Earliest$-$Finish$-$

Time First $($EFF$)$

Sort the intervals by their finish times in ascending order. Assign each interval to the first available room.

The resulting assignment for the given set of intervals is as follows:

Room $1$: $(1,4),(5,7)$

Room $2$: $(3,6)$

Room $3$: $(2,8),(6,9)$

Why the $(6,9)$ is at Room $3,$ not in Room $2?$