In episode 9, Jack talks about his memories of the past, and how they are just memories. People he's helped, people he's seen killed by Aku and his minions, all of that are just memories. He doesn't want Ashi to be just another memory, which is why he took off and left her at space ship thing.
He has no way home, and realizes that when he sees the shattered remains of the Guardian's portal, and the Guardian's shattered glasses.
The Guardian may be alive, as so far this season every time someone has died, we've seen them die.
Jack, I think, has realized that he cannot go back to the past, and given the choice between going back to the past and staying with Ashi, he's gonna stay with her.
As to next episode... There's so much that's been getting packed into these episodes that 10 is gonna be a hell of a rollercoaster. They have to touch on the Scotsman's army, Ashi being saved/killed-then-coming-back, Jack getting the resolve to defeat Aku, and probably a few other things I'm forgetting.
I can't even make a prediction to what is gonna happen, there's too many things that have to go on.