Hi GLEN,
If your form is create by InfoPath, you can set it easy. But your form is Adobe LiveCycle ES9.0,it is difficult to achieve it out of the box. So, you may be read your adobe form by coding, then use SharePoint Event handler to fill your column.
You can refer to the following link.
http://jadn.co.uk/w/ReadPdfUsingCsharp.htm
Thanks,
Jack