Chapter seven of Chronicles demonstrates that while the emphasis in these genealogies is on the southern kingdom, they are not the only ones returned to the Land of Promise. The other tribes have made their way home as well, and have likewise kept their ethnicity pure as can be seen by the genealogical list they have preserved.
Close comparison of 1 Chronicles 9 with Nehemiah 11 will reveals some differences in numbering. This is not to say they contradict. It only says that the writer of Chronicles and the writer of Nehemiah wrote at different times – perhaps a generation apart. That would give us a date for Chronicles of about 400 BC.
As newly reconstituted Israel begins to make their way and look toward nationalistic expectations, the writer of Chronicles wants them to remember that God is with them, and will bless them, if they will but submit to God’s rule. Failure will lead where they’ve been – to exile.