RCD and CD Front 9's are definitely the best 9 holes stretches I've seen. My other favorites;
Kirtland CC Back 9 (Ironic that one of the best holes is on the front ~ #9)
Sunningdale New Front 9 (#4-#6 is one of my favorite stretches in golf)
Streamsong Blue Front 9 (#2-#7 and #9 are fantastic holes that don't get enough love)
Kingsley Club Front 9 (#2, #3, #8, #9 are my four favorite holes on property. They should flip the 9's imo)