I want to know that can a woman kiss the hand of an elderly non-mahram man (Pir sahab) out of respect?
No its not permissible, but its only permissible for men as it was a common practice in the history and of golden era.
Its not even permissible to shake hands and go in front of him without hijab, with the elderly
peers if you want to perform bay'ah you need to be in hijab or behind of curtain and do the bay'ah.
As we can see in the books of ahadeeths, when women used to come for bay'ah then prophet Muhammad (Peace be upon him) not used to shake hands with them instead they used to do bay'ah wordily.
Its best not to do that as Shriya prohibts Non Mahram contact of all sorts and if its kissing hands today tomorrow it could be other things as the Neyia of that even old man could be evil and my revert question to you is why are you going such places where you have to kiss some oldmans hand.?
Whynot just follow quran and saheeh sunna / hadith that being said a real shaikh or a man of Allah/religon will never allow you to touch him / kissing hand is far far beyond for such a man of faith and pioty if this quality is not in your Shaikh then you need to leave him.
May Allah protect all our sisters from harm and such men.