Yes, you can set up a SMF poll to view or not view. When you create the poll the option should be presented to you at that time. There are other poll options too.
The version of SMF that these forums are hosted on is outdated. There is a newer version available. I'm not sure they add features, but it probably has some security holes plugged.
These are the options you see when you create a new poll on these forums. The three bullets in the middle define who can see the poll results and when.