1. The meaning is different: five dragons symbolize imperial power and the world, while nine dragons symbolize wealth, evil spirits, prosperity and wealth.
2. The production quantity is different: the oolong seal is singular, and the Jiulong seal is even.
3. Different historical background: Wulong Seal is the symbol of Qin Shihuang. The Han dynasty followed the Qin system and also used the five dragon seals. In the Tang Dynasty, the Oolong Seal became the symbol of the supreme ruler, and the Song and Yuan Dynasties changed to the Kowloon Seal. Kowloon Seal was used in Ming and Qing Dynasties.
I hope the above information is helpful to you. If you have any other questions, please let me know.