7
You should never have to go into the settings of the actual XoopsPoll module. If the XoopsPoll module is installed, you should get a button right next to the new topic button saying new poll, just like Ghia says.
Go to the settings of the CBB module, on the Permissions tab, select Can Add Poll from the dropdown and make sure the relevant groups have access.
I've tried this myself with XoopsPoll 1.3 and CBB 3.08/CBB 4.02/X-Forum 4.12.