Walk from Windy Ridge to Narcissus for the 9:30am ferry?

Hello OT experts,
I'm planning an OT walk for late Jan 2014 and have a quick reality question that I can't find an answer to yet: Is it realistic to get up early and walk the 9km (3-4 hours) from Windy Ridge to Narcissus to arrive in time for the pre-booked 9:30am ferry to Cynthia Bay?
I need to be on that ferry to get the Tuesday 11:45am TassieLink bus out to Hobart. It seems like it would just need to be an early start (9:30am ferry with 3-4 hrs walking means at latest a 5:30-6:30am walk start), but I can't find any mention of other hikers who have done this hike/ferry schedule on their final day (perhaps it's so common that nobody mentions it!). As a first time OT walker, my plan is to stick to a standard 6 day itinerary (including little side trips where time permits): Ronny -> WFV -> Lk Windy -> Pelion -> KO -> Windy Ridge -> Narcissus.
Please note: I am aware of, and unbothered by, the argument regarding whether the OT really 'finishes' at Narcissus or Cynthia Bay - for me, this hike will end at Narcissus.
Many thanks for your feedback,
LFRF
I'm planning an OT walk for late Jan 2014 and have a quick reality question that I can't find an answer to yet: Is it realistic to get up early and walk the 9km (3-4 hours) from Windy Ridge to Narcissus to arrive in time for the pre-booked 9:30am ferry to Cynthia Bay?
I need to be on that ferry to get the Tuesday 11:45am TassieLink bus out to Hobart. It seems like it would just need to be an early start (9:30am ferry with 3-4 hrs walking means at latest a 5:30-6:30am walk start), but I can't find any mention of other hikers who have done this hike/ferry schedule on their final day (perhaps it's so common that nobody mentions it!). As a first time OT walker, my plan is to stick to a standard 6 day itinerary (including little side trips where time permits): Ronny -> WFV -> Lk Windy -> Pelion -> KO -> Windy Ridge -> Narcissus.
Please note: I am aware of, and unbothered by, the argument regarding whether the OT really 'finishes' at Narcissus or Cynthia Bay - for me, this hike will end at Narcissus.
Many thanks for your feedback,
LFRF