I believe the only difference between the tail on the 9 and 9A is the holes in the lowest rudder hinge bracket mounted on the spar of the vertical stabilizer. If you're building a 9A you use two rivets in the lower corners of the bracket. If you're building a 9 the holes will eventually get drilled for bolts, which I believe somehow attach to the tailwheel assembly.
Van's doesn't even know what you're building (9/9A) until you order the fuse kit, so they won't care. If the kit is unfinished, it is very likely that this step would not have been completed yet.