If I look at the fields available under v8.2 and v9.0 on Campaign Activity and Campaign Response I see some big differences:

• Campaign Activity:
  
  
  
  • v8.2:
    
    
    
    • 51 Fields
    
    
    • Only 2 Party List Fields
    
    
    
    
  
  
  • v9.0:
    
    
    
    • 77 Fields
    
    
    • 10 Party List Fields
    
    
    • Many other fields no present in v8.2
    
    
    
    
  
  
  
  


• Campaign Response:
  
  
  
  • v8.2:
    
    
    
    • 58 Fields
    
    
    • Only 3 Party List Fields
    
    
    
    
  
  
  • v9.0:
    
    
    
    • 84 Fields
    
    
    • 12 Party List Fields
    
    
    • Confusing duplication:
      
      
      
      • Customer cf. Customers
      
      
      • Parter/Outsourced Vendor cf. Partners/Outsourced Vendors
      
      
      
      
    
    
    • Many other fields no present in v8.2
    
    
    
    
  
  
  
  

What is going on?  It doesn't seem even close to what is documented here:

https://docs.microsoft.com/en-us/dynamics365/customer-engagement/developer/activityparty-entity#activity-party-types-available-for-each-activity

See attached screenshots.