We have made it possible to rename Sexy Polling to Fancy Polling by using our Fancy Polling plugin for Joomla.
To change the name you will need to setup the Fancy Polling plugin on your Joomla website and enable it.
You can download it here: plg_fancypolling.1.0.0.zip
This change makes it possible to use the Sexy Polling extension safely on school websites and other websites which cannot accept the plugin naming.
Edit: After you enable System - Fancy Polling plugin make sure to reorder the system plugins, so System - Fancy Polling plugin is after Fancy Polling or Sexy Polling plugin.