If the big final battle is still going to end the way it was told in the "Fray" series, then there can't really be that big final Alamo/300 Spartans/everybody goes down swinging ending this season and still be a Season 9, which I believe has been pretty much promised to us by Joss. Most likely, that battle will be the climax of Season 9, unless sales are so great that a Season 10, and even more, are required.
My notions of what Joss is going to do with season 8 come mostly from this quote, from
this interview:
"I was dealing with the fact that I had created a future where none of the things she had apparently accomplished had actually happened"”I wrote them before I wrote her doing them, and that was a mistake. So trying to reconcile the two led to the tone of season eight. It is a little intense but it hopefully has a goofy side to it."
The future he created was "Fray," the "things she had apparently accomplished" was the big battle depicted therein. So Joss wanted season 8 to end with showing us that big battle and hooking up the two stories.
But the Great Victory doesn't have to be the end of the story. After the V-J Day ticker-tape parades ended everybody had to go find jobs and get re-acquainted with their families and deal with the memories of what they'd seen. The Aftermath can have just as many good stories as the war.
Plus, when it comes right down to it, it's never actually been established that Buffy is the Slayer who leads that final battle. According to the original text from "Fray" #2, the only definite thing that we know is that the battle takes place in the early part of the 21st Century. And even that is suspect, seeing as how the information comes from a demon and later from what appear to be Watcher archives, which may not be that accurate or even authentic.
But really, what other Slayer would it be? After 12+ years of Buffy's story, I don't think some other new gal is going to come waltzing in and win the ultimate battle. The Slayer we see in the comic is wearing a miniskirt and has hair just like Buffy's.
Remember, by Fray's time, the Watchers have devolved into a pack of suicidal lunatics. Who's to say that they didn't edit the actual events or even fabricate the whole thing? And are they even the authentic Watchers? According to the "No Future For You" arc, Giles is, essentially, all that is left of the Watchers, and he doesn't seem that intent on er-establishing the group anytime in the near future, certainly not soon enough to have it up and running in time to record first hand the events of any armagedon taking place anytime soon.
He already has re-established the Watchers in a limited respect. Andrew and (I believe) Robin Wood are performing Watcher duties under his supervision. The books Mel finds don't tell about the final battle, just about the Slayers. It's Urkonn who tells her about the battle, and usually when you see explication spelled out like that, it's the truth. There was never any revealed reason for him to lie about it.
The entire "everything gets sucked into Hell" scenario might even have been a huge mix up, combining the events of "Angel: After The Fall" with whatever battle is actually coming, especially if there is any kind of crossover between the two magazines. Such inaccuracies happen concerning real historical events, and there's no reason to think that the same thing couldn't happen in the Buffyverse.
All we see in "Fray" is Buffy herself getting sucked into (or possibly out of) Hell or some similar dimension behind a portal. Not certain if anyone else goes with her.
The final battle scene shown in "Fray" actually looks very similar to the scene of the approaching demon army at the end of "Not Fade Away." This was what led me to believe that maybe Wolfram & Hart were going to be the Final Bosses Buffy (and Angel) had to fight.
"Fray" was published during Buffy season 7, a year before "Not Fade Away," so it may have been no accident that the two battles looked similar.