On 99% of the planet, if a 17yo acts like, and is willing to screw your brains out, you're good to go and quite legal. In fact, same for a 16yo. In fact, on half the planet including a large portion stateside, that works for 15 too.
The fact that you bring up morals here is very telling. Sex is not some magical scary thing that's worse than murder, and should stay hidden and never talked about. It's... just sex. It doesn't matter if there is a power imbalance - women find powerful men attractive. The power imbalance can't be used at work on a screw me or get fired basis, but it can be used in "I'm powerful and that scores me points with you."
Now if someone is a hooker and under 18, but you're not hiring the hooker nor know she is a hooker, guess what... You did nothing wrong, neither did the hooker, nor is sex work "immoral." The guy the hooker works for did something wrong and... died for it. All is well, undersexed people need to stop poking their nose in other people's assholes.