how to get from Kiel cruise port to Hamburg center

Try rome2rio.com. As well, your cruise ship excursion director will help you with ideas.

You can take a short taxi ride or bus #41 from the cruise port to the main train station (Kiel hbf), where there are trains every half-hour to Hamburg, taking a little over an hour. Just buy tickets upon arrival (about 22 euro). See www.bahn.com for train schedules

Assuming that you get into the regular Cruise Port in Kiel, which is right near Sweden Quay, there is a DB bus from Sweden Quay (Schwedenkai) to Hamburg airport, from where it is a 30 mins S-Bahn ride into the city center.

http://www.bahn.de/autokraft/view/index.shtml