Yes, it is a noun; it is a proper noun because it is the name of a person.
Yes, Alison is a proper noun; a person's name is always a proper noun, first and last.
Brandon Desmyter is a soccer player at DeWitt High School in Michigan. He has been All-League, All-District, and All-State, and will be team captain in 2015.
Alison Levine goes by Alison Hartwick Levine.
Alison Cronin's birth name is Alison Ames.
Alison Lohman's birth name is Alison Marion Lohman.
Alison Corino goes by Alison Danger.
Taylor Swift's middle name is Alison and by the way, she is my favorite singer!
Alison = 'Alikoni
Alison Sudol's birth name is Alison Sudol.
Alison Stern's birth name is Berns, Alison.
Alison Knowles has written: 'Untitled by Alison Knowles'
Alison Sweeney was born on September 19, 1976.