Yes you can. PappaShop does not offer support for any programs found in the CPanel since its all third party software, however you are welcome to install whatever you would like. When you install anything in the Fantastico or Softaculous area, always make a new directory where it asks where to install to. For example, if its a blog, write the word "blog" in the box where it asks what directory and that directory will automatically be created to install into. That way no important main website files are overwritten accidently.
Should you need assistance with any program you have installed from within the Fantastico and Softaculous section of the CPanel, each company has its own support system if you visit their website.