If his son followed his views it would seem unlikely. He was married in the 'relief congregation' church Irvine.
https://www.rootschat.com/forum/index.php?topic=367866.0
( Just to add. I found that the marriage took place just after an interesting time in the history of that particular church https://en.m.wikipedia.org/wiki/Buchanites )
I found this link which has books about the Jacobite Rising which might help. I found one mine listed in the Books.
https://www.scottishhistory.org/articles/siege-of-blair-castle/
https://www.wikitree.com/wiki/Agnew-738
Billie