Sorry for the delay in response to your query. As per the description above, you are not able to activate Adobe on iMac, Is that correct?
The records show that you an active subscription of Adobe ExportPDF, Annual subscription on your Adobe Id.
Adobe Export PDF is an online Adobe Document Cloud service. It's not an application and cannot be activated.
For more info: Using Adobe Export PDF
To use the service, log in to your account at https://cloud.acrobat.com/exportpdf with your Adobe ID and password.
You may also download the Adobe Reader(Free Adobe desktop app) to use the service: PDF reader, PDF viewer | Adobe Acrobat Reader DC
Feel free to update this discussion in case you need further assistance.
Thank you. This is resolved now.