Is david a noun or pronoun?

The Word David is a noun, a proper noun, the name of a person.

A proper noun is always capitalized.

A pronoun is a Word that takes the place of a noun in a sentence. The pronouns that take the place of the noun David are 'he' as a subject, and 'him' as an object. Examples:

My brother David attends the state college. I miss him when he's away.