Who is the Rams fan on the list?
Magic Johnson is retired from the NBA, where his career teams included the Los Angeles Lakers. Reuters, in a report carried by Yahoo Sports on January 18, 2016, quoted him saying "I'm so excited and can't wait to see OUR team next season!" The tier here is Reported: the fandom comes through the outlet's account, not from Johnson stating it himself in a sourced interview.
Does his background line up with the Rams?
Only partly, and only where the sourcing shows it. Magic Johnson was born August 14, 1959, in Lansing, Michigan, and attended Everett High School there. His career teams include the Los Angeles Lakers, a Los Angeles franchise, which sits in the same city as the Rams, though nothing ties his fandom to that.
Questions people ask
Which athletes are Rams fans?
Magic Johnson, the retired NBA player, is reported to be one, by Reuters in January 2016.
Which athletes grew up Rams fans?
Nothing says Magic Johnson rooted for the Rams as a child; the report concerns his excitement for the team in 2016.
Did Magic Johnson say he is a Rams fan himself?
Reuters reported it with a quote from him, but the fandom is Reported, not confirmed in his own words.