In the early 2000s, there was a widespread practical joke in which people listed themselves as having the religion Jedi on their census records. The joke was spread by emails. As a result, there were thousands of Jedis listed in the census records in the United Kingdom, Australia and New Zealand in that period. Although it was mainly census records that were affected, it is possible that some people continued the joke in other records.
In fact, Jedi was not a real religion, but a reference to a quasi religious/military order in a series of popular movies, collectively known as Star Wars, which first appeared in the late 1970s. The heroes of those movies were Jedi Knights (or just Jedis).
Finding a reference to a religion of Jedi from the 1970s onwards should therefore be treated with some suspicion. It probably suggests the person had a sense of humour rather than any strong religious beliefs.