I'm printing a duplexed booklet with vertical master spreads using the instructions by Cari Jansen (great tut) http://indesignsecrets.com/vertical-master-page-spreads.php/comment-page-1. But when I go to print, the pages will not print vertically. There must be a setting I'm missing or it not possible to print a calendar style booklet (duplexed - long side) using the Print Booklet plugin. There were a couple people that had the same issue but no answers to their question. Hopefully someone knows the answer.
A "booklet" is typically horizontal, not vertical. I don't think you can use the Print Booklet command to create a vertical booklet.
That being written, there is nothing stopping you from adjusting the InDesign layout and rotating the page contents (not the page) 90°CCW and them printing it that way.