Display Categories option doesn´t work in front page

I have a blog where my home page displays every post I make and and the other pages are filtered by category. I have configured the main page so it would display the category as a short text just beside the date, but no matter what I do I can´t get it working.

You can see the home page here
http://www.leigojaonevis.com.br

and a subpage where the categories are visible in each post.
http://www.leigojaonevis.com.br/textoteca/

Can you please assist?

Regards.