Cynthians had discovered the hyperdrive independently. Of course not. Since Chee Lan is introduced in "The Trouble Twisters," this is where the introductory data about Cynthia are presented:
when discovered, an Alexandrine technological level on one continent;
trade routes instead of nations;
well adapted to fit into the League;
white Angora fur on the dominant species.
We learn elsewhere that:
the trade routes are in the treetops;
Cynthians become independent spacefarers;
they build a forest village on Daedalus;
the trade routes that join the League do not help other Cynthians to develop economically;
some underdeveloped trade routes join Supermetals.