Complex sentence: The World Taekwondo Federation (WTF) awarded Ahn his Master Instructor certification in 1977, and he received 9th "dan" ranking from Kukkiwon in 1990.
Split into simpler sentences: The World Taekwondo Federation (WTF) awarded Ahn his Master Instructor certification in 1977. He received 9th "dan" ranking from Kukkiwon in 1990.