Can I adjust the pattern to fit my fabric which has a horizontal repeat of 9”?
You shouldn’t change the pattern. If necessary you can cut each piece separately to place the fabric as you choose. Then sew the pieces back to-gether.

What is the difference between the Sheffield and the Imperial Valance?
The Sheffield has a straight “box pleat” as opposed to the Imperial “horn”.

Can the Sheffield jabot be used with the Imperial Valance?
Yes. The Sheffield jabot is used as a separate unit on the valance and could be used that way with other valances.