Saw in today Malaysia's Min Sheng Bao [民生報] (ed: PP5749/12/2007):
A brief translation for our 'overseas' friends:
"Regarding the origin of the following of the 9 Emperor cult, few people are sure. However, it was known that the first source was from Phuket, Thailand, from the Kathoo District) and arrived at Taiping, Perak, around 1828, brought there by a Fujianese from Chiangxi, China. Around 1855. a strange sckness falls upon (mainly old folks in this town). Someone from the 9 Emperor temple advised the old folks to take the 9 Emperor vegetation foods and miraclely, all the old folks that have this sickness was soon cured. Thus spreaded the worship of the 9 Emperor!
Another connection is the Dou Mu temple in Hong Kong Street, Penang. The first Dou Mu temple in Hong Kong Street, Penang is believed to be built in 1842. It is believed to be the oldest Dou Mu Temple in Malaysia. This temple processed a sacred 9 Emperor's scriptures (made of silk and hand embroided) consisting of 32 pages. This sacred scripture is known as Jiu Huang Sheng Jing [九皇圣经]. it was mentioned in this sacred scripture that these 9 Emperor are the 9 Northern Stars Deity.
There are also many other 'legends' regarding the origin of the 9 Emperor. Some said that they are nine scholars who committed suicide to protest against the Emperor; Another source said that they are 9 bandits that were killed. However, everyone agreed that the 9 Emperor bring them good luck and health.
On the 9th Day of the 9th Lunar month, in Penang, there's another special festival. People, young and old, will climb the Penang Hill (known as Sheng Ji Shan/升二山), for on top of this hill, there's a temple known as Qian Er Ceng (千二层) to pray respect to the 9 Emperor. some old folks will do the "3 knee 9 kowtow" all the way to the top! WOW!