ch.9 opens with the words:

Captain Wentworth was come to Kellynch as to a home, to stay as long as he liked, being as thoroughly the object of the Admiral's fraternal kindness as of his wife's.
When I read this I wondered whether he might constantly be reminded of Anne when he walked through the rooms at Kellynch. I guess that most of the furniture was still at its place and although Anne wasnīt present he might even at his sisters new home be thinking perpetually of her.

That they did meet at Kellynch Hall eight years ago is seen in ch.11 when Annes thoughts go wandering:
She wished it might be possible for her to avoid ever seeing Captain Wentworth at the hall: those rooms had witnessed former meetings which would be brought too painfully before her.
Well, I just realize that in the original text it just says hall - in my translation it says Kellynch Hall...