Hendry, a Stephen Gallacher Foundation Winter Development player, reeled off eight birdies in a closing 68 at the Perthshire venue, having opened with scores of 73-75.
His total was matched by Nairn’s Alex McGillivray, but Hendry came out on top at the first extra hole in a sudden-death play-off.
The girls’ title was landed by Freya Russell, who plays her golf at Royal Troon but is a Stephen Gallacher Foundation ambassador.
Russell carded rounds of 75-74-76 to win by a shot from Forfar’s Robyn Fowlie.
It was Russell’s second big success this year, having already landed a runaway win in the Stephen Gallacher Foundation Masters at Dundonald Links.
The next big junior events are the Stephen Gallacher Foundation Trophy and Vase at Cardrona near Peebles on 11-12 June.