If you have already activated a license or used eM Client before on that device, you won’t get a second evaluation period. You only get one 30 day evaluation per device. Unfortunately you don’t get another evaluation period for each major version when it is released.
However, we will be releasing version 10 later this year. The beta is available for testing and you don’t need a license to do that. If you won’t to try it, see: eM Client 10 BETA is here!