First off, these teams are fundamentally different in a number of important ways, so please don't think I'm trying to compare them on their merits. I'm not. I just think the schedule parallels and oddities really are quite striking:
In 2004, after nine games, the Bills were 3-6. They had a first-year, offense-minded head coach. They were averaging 16 points and allowing 19, a pythagorean estimation of 3.48 wins through nine games, suggesting they were underperforming a bit. Their full-season estimation was that of a 6.2-win team. Then, in the final seven games, they went 6-1, averaging 36 and allowing 17. They had a win estimation of exactly 6 (13.7 wins in a 16-game season). So what changed?
Well, the schedule. Primarily due to playing the NFC West. The Bills, over the course of the first 9 games, played six against teams with .500 or better records, including three that would go to the playoffs. Over the rest of the year, they got three bad NFC West teams (this is back when everyone in that division was terrible), the 4-win Dolphins and Browns, beat a decent Cincinnati team on the road, and then endured the infamous game against the Steelers' backups (aka. the Willie Parker game).
They kicked it into high gear against some pretty terrible opposition, road a winning streak, inspired play from Drew Bledsoe, and an opportunistic defense to nearly make the playoffs.
Now, for the similarities. The Bills this season are 3-6, scoring 21 points and allowing 26 (and a bit inflated by defensive/ST TDs), a close differential when you correct for the D/ST score imbalance.
They have only played two teams under .500, and those are Baltimore and Cleveland. A whopping six of their nine games were against teams currently sitting in playoff spots (and they played all of them except New Orleans close, as you'll recall). Over the remainder of the season, though, they get four teams with 2 wins or less, the Dolphins and Jets at home, and a potentially-clinched division leader in the last game of the season.
They're relying on weak opposition, an improving QB situation, a first-year head coach, and an improving defense while trying to ride a string of wins to a potential playoff spot.
Let's just hope it doesn't become known as the "Cierre Wood game".