In COSMIC TRIGGER, VOLUME TWO: Down to Earth," Robert Anton Wilson discusses his Buddhist wedding (in the chapter "The Sangha ... Light in Manifestation," and his interest in Amida Buddhism. He explains that Amida Buddhism is "based on faith in Amida, the Buddha of compassion. Amida refused to accept Nirvana until every sentient being could enter the blessed quenched state along with him."
This is correct, but also a little bit incorrect, a little bit like saying that Methodists don't accept the authority of the Pope. That would be true, too, of course, but it leaves out the fact that Methodists are Protestants, none of whom accept the authority of the Pope.
Broadly speaking, Buddhism tends to divide into two main groups -- Theravada, the "old school" Buddhism mainly practiced in the south of Asia, such as Sri Lanka, Thailand, and Burma, and Mahayana, the later developments such as Zen, which are practiced in northern countries such as China and Japan. In Mahayana, a bodhisattva is someone who has attained enlightenment, or at least is pretty far along, and who dedicates his life to sharing what he has learned to help others attain liberation. In some cases, this is depicted as renouncing nirvana in favor of compassionately helping others. (More here.) Amida Buddhism is a form of Mahayana.
(Rock music fans of a certain age may remember the term from the Steely Dan song, "Bodhisattva," from the band's second album, 1973's "Countdown to Ecstacy.")
I ran across a posting on the San Francisco Bay Craiglist's a few weeks ago that referred to Wilson, Krishnamurti and Terence McKenna as "Buddhas." (It's expired, so I can't link to it.) I don't know what to think about that, but couldn't Wilson be termed a bodhisattva? He gain some measure of enlightenment, and spent much of his life sharing what he learned.