I don't really see a way J. Smith, Monroe, Stafford, Raji, Crabtree, Orakpo or Curry make it out of the top 9. The only one with a chance is Crabtree, and if he does the Niners should snatch him up with the quickness.
That leaves A. Smith, Maclin, Sanchez, Jenkins, and Brown to pick from. There will probably be a surprise player in the top 9 so the Niners will probably have their choice of 3-4 of those guys.
I like Brown the least of all those players. In fact, I'd prefer Maybin to Brown if they want to reach for a pass rusher.
Without being able to sit in on interviews it's hard to say who would be the best choice. Jenkins is probably the safest as a FS. Sanchez has the most upside if he pans out. Maclin is kinda in the middle.
I also wouldn't toss out Smith. He's not in great shape, but he was even fatter during the season and punking fools.