9 day visit in May 2019 Suggestions?

For Berlin I suggest 4 full days, maybe plus 1 for Oranienburg.

In Berlin for Holocaust I suggest:
+ German Historic Museum
+ Topography of Terror
+ Holocaust Memorials
+ Sachsenhausen at Oranienburg if you not have been to Dachau before
+ Gleis 17 and House of The Wannsee Conference

And also do not forget the other few hundred sights: https://www.visitberlin.de/en :-)

Best mode of fast and cheap mobility in Berlin is public transport.

Easily done. Is this 9 days or 9 nights? If 9 nights, spend 3 in Munich, 2 in Nuremberg, and 4 in Berlin. Munich public transport from airport to city, city to Dachau and back is cheap and easy. Frequent trains to Nuremberg and then to Berlin. You can buy nonrefundable train tickets well in advance for little money. Berlin city transit is also cheap and easy and a lot to see there. Holocaust memorial, Topography of Terror, vestiges of the Berlin Wall, the Reichstag.

Trains: https://www.bahn.com/en/view/index.shtml
Munich transit: https://www.mvv-muenchen.de/en/index.html
Berlin Transit: http://www.bvg.de/en/
Nuremberg Transit: https://www.vgn.de/en/

Thanks MarkK andSam for the quick responses. I am staying 9 nights. Do you think a side trip to Salzburg is too much?

Salzburg - depends on your Munich program and your jetlag :-) I recommend not to over"kill" the time you have.

thx understood.

Sam's proposed outline for the trip looks good. I would just say don't get too carried away with Holocaust and Nazi sites. Find fun things to do, too. If Salzburg would bring a little joy to your trip, I am strongly supportive of a day trip there.

I enjoy walks in parks. Lonely Planet has a pleasant "leisurely Tiergarten meander" that you can find if you google it. Look for the Google Books link which gives full details and a map. I also like to wander Volkspark Friedrichshain in the late afternoon/early evening with a stop at the Märchenbrunnen, the fairy-tale fountain at one corner of the park; a walk in this park gives a good opportunity to see Berliners being Berliners.

TY Dave, I like the Berliners being Berliners. That's all part of the experience as it should be.

You can visit to europe.