If you want to hand in your master thesis for the exam period of January, you have to apply for this by Dec 1. The form is available on the website of the faculty:
Dutch version: http://we.vub.ac.be/files/formulieren/aanvraag%20afstuderen%20eerste%20…
English version: http://we.vub.ac.be/english/docs/Application%20graduation%20January.doc
The deadline for handing in your thesis is January 10th.