If you want to prevent the user from submitting multi times the poll, you can use personalization to hide the poll and show the result. Therefore, you can use Goals. Or create a personalization rule. This demo contains 2 rules. To personalize on filled in Car color or not, or personalize on the value.
To see the values easy in the XP profile it is handy to register the user and give a Name, this can be easy done with Sitecore Forms Extensions and the xDB ValueProvider from https://github.com/bartverdonck/Sitecore-Forms-Extensions This way you can easy create a form with fields that are pre filled with the values stored in XB and they are also stored in xDB, When filling in a name, it is easier to find the user in the xDB profile.Don't forget the Store Binding value.