about to install the recent purchased captivate 9, however i need my Serial Number. Where can i get it?

You need the serial number if you have a perpetual license. If you have a subscription license, just install the trial version. When you start Captivate with your Adobe ID (the one linked with the subscription license), it will be recognized.

Moving to Adobe Captivate‌

Find your serial # http://helpx.adobe.com/x-productkb/global/find-serial-number.html