The first capital of Rus was Novgorod before Kiev, regardness of Rurik's nationality.
Сoncerning the succession between Kievan Rus and Ukraine – I can quote an interesting words of Hrushevsky, but it would be seen as a

Old Ladoga, to be technical. ;)
But that was only during period of consolidation. So, Kiev may rightfully occupy the place of first capital of Rus in the full sense of the word.