They are two different words Creepy does not mean offensive. Ive never heard the words interchanged.
of·fen·sive /əˈfɛnsɪv or, for 4, 5, ˈɔfɛn-, ˈɒfɛn-/ Show Spelled
[uh-fen-siv or, for 4, 5, aw-fen-, of-en-] Show IPA
–adjective
1. causing resentful displeasure; highly irritating, angering, or annoying: offensive television commercials.
2. unpleasant or disagreeable to the sense: an offensive odor.
3. repugnant to the moral sense, good taste, or the like; insulting: an offensive remark; an offensive joke.
4. pertaining to offense or attack: the offensive movements of their troops.
5. characterized by attack; aggressive: offensive warfare.
creepy (ˈkriːpɪ)
— adj , creepier , creepiest
1. informal having or causing a sensation of repulsion, horror, or fear, as of creatures crawling on the skin
2. creeping; slow-moving