The short answer; Yes you can.
And in more detail, yes but… If you simply disable the free version and leave it be, that’s fine. But many like to remove the plugin. Which is better.
Every purchase of an AdRotate Pro license comes with a readme file which has a step-by-step manual on how to upgrade to AdRotate Pro and what to do with the free version.
There is also a guide in the AdRotate Manuals section which you can get to via this direct link: ajdg.solutions/manuals/adrotate-manuals/upgrade-adrotate-to-adrotate-pro/.
Just when you think you find a nice quiet beach for a swim and you’re constantly stung by shrimps… 🙁