Final answer:
Billy Crystal agreed to host the 84th annual Academy Awards for the 9th time, showcasing his long-standing role as a beloved and comedic Oscars host.
Step-by-step explanation:
The person who agreed to host the 84th annual Academy Awards for the 9th time is Billy Crystal. Billy Crystal is a well-known actor, comedian, and awards show host. Over the years, he has become one of the most memorable Oscar hosts, known for his ability to engage the audience with humor and charm. Comedians like Billy Crystal have a long-standing relationship with award shows, and Crystal, in particular, is beloved for his multiple stints as the Oscars host.