I wonder if episode 9 will be entirely in the Winterfell area like Blackwater (2.09) and Watchers on the Wall (4.09) ? or more like Hardhome (5.08), only the last 25 minutes ?
A Winterfell focused episode is more likely though. I don't see D&D breaking the tradition, they seem to follow the every 2 years pattern (2.09>4.09>6.09) for big battle episode. This episode will be 60 minutes, which is a lot for only one area 

 But they have a lot to cover if 6.08 has no north plotline. We should get quite a handful of talking scenes revolving around Jon, Davos, Sansa, Tormund, Ramsey, Rickon and all the lords involved in both side (Karstark, Umber, Mormont ect ...) + the bonus cards: Littlefinger and Melisandre, then the last 25 minutes should be full-on action.
I really hope Melisandre gets to shine again in some way, she's been a ghost this season. Giver her something please. In season 2 she wanted to help Stannis with her magic for the Blackwater battle, she said so herself but Stannis listened to Davos, told her to stay away and do nothing.