Is there any easy way in adding a short title, author, date, etc. in the .org file, without messing around with the generated .tex file?
My (in progress) Org Beamer refcard could help you.
See on https://github.com/fniessen/refcard-org-beamer, in particular the section "Creating a title page".
UPDATE -- Something like the following would do it?
#+BIND: org-latex-title-command "\\title{De leerplandoelstellingen}\n\\date[mei 2014]{9 mei 2014}\n\\maketitle"
(that's a way to fiddle with the title, but directly from the Org file...)