I'm not sure whether I understand exactly what you are asking, but attempting to clarify:
You arrive at Copenhagen to go on a cruise. Before the cruise you have a booking at the Copenhagen Crowne Plaza (at Ørestad). After the cruise: your ship is docking and you will be disembarking at 10 AM. The day after disembarking from the cruise you are flying out at 8.20 AM, and now you are asking whether you should stay in town or closer to/ at the airport.
In your situation, I would definitelty stay at the airport Hilton, if you could snag a good rate. I certainly would rather pay USD 300 at the Hilton than at either of the Radissons! The refurbished d'Angleterre would of course be something else when it reopens...
The convenience of not having to transfer to the airport at 6 AM in the morning is more than worth the extra metro trip back to downtown. You would in any case have a significant transfer from the ship in the morning, so adding an extra 10 minutes to go to Kastrup is of no significance. As you might gather, the airport Hilton is the Copenhagen hotel of choice for many on this forum. The Radisson is OK for Tivoli and the Central Station (which have to be accessed by local train, not Metro from the airport; just as quick but not as frequent or reliable in my experience, YMMV) USD 300 is expensive though.
The Crowne Plaza is on the airport metro line, one or two stops from the airport. I don't know the hotel, but the area is rather non-descript, and the location is neither downtown, nor airport proper.
you absolutely got my situation correct.
we are flying from sydney direct to CPH so thought we wouldnt want to go into town that night anyway so when the 5000 pts CP deal came in we thought it appropriate'
the reason i was thinking radisson was the 50k bonus which finishes the net day.
i would love to do the hilton but am torn on the 50k bonus against no promo with hilton.
but thankyou for your imput it is very much appreciated. apparently we are going to the freeport terminal I can only imagine the cost to and from!