Hi Roger,
We don't have a 9 user license, but if you purchase a 3 user Standard license then you'll give access to 9 machines. The licenses are cumulative so you can add to them.
Alternatively you can upgrade your 6 user license to a 12 user license, just enter your license details into our online upgrade wizard and you'll see all of your upgrade options. You'll find it
here, choose Upgrade an existing license from the blue box.