Hmm my initial reaction is surely not and that sexual repression is such a cliche.
Maybe, but clichés have a basis in reality. The whole story is dripping with sex whichever interpretation you choose to believe. People at that time were sexual beings in exactly as we are now, but any sex other than between married couples was frowned upon.
The sexual repression theory isn't mine, although I think it is a pretty obvious (rather than clichéd) one, and is hinted at even in the introductory section. The critic Edmund Wilson wrote a book called The Ambiguity of Henry James in which he clearly advocates the theory that the narrator is 'a neurotic case of sex repression' who has conjured up the whole story to attract the attention of the handsome guardian, with whom she admits she had been 'carried away' when she met him.
However, the ghost story is equally compelling. The relationship between Quint and Miss Jessel, as described by Mrs Grose, is clearly sexual, as well as being abusive and controlling (in todays terms) and she is clear that he was a malign influence on the young woman and on the children. Miles behaviour is worrying, why is he sent home from school? We never find out, it's obviously something bad but no one will state openly what it is, the implication is strong that it's as a result of him being exposed to corruption, or 'grooming' by Quint.
SPOILER
Either narrative can be accepted as being the truth but the fact is that Miles dies. Is it because an evil ghost has taken him? It's a ghost story, why not? If not then the narrator must be responsible for his death in some way - both alternatives are horrific, that's the strength of the story, and why it's so brilliant