The 16-year-old, who also plays age-grade football for her country, defeated 20-year-old Elspeth Young from Kinross 11-4, 5-11, 11-6, 12-10.
In the men's event Scottish number one Alan Clyne, who has risen to world number 32, beat Douglas Kempsell.
He won 11-5, 11-5, 11-2 to earn his seventh Scottish title.
The 30-year-old from Inverness said: "I felt good going through the rounds, but I knew that Douglas would put up a real fight in the final because we all know he is a battler.
"That was the way that it panned out, but I managed to get on the front foot and take the win.
"I am often playing abroad, so I love getting a chance to play in Scottish tournaments and I am very proud to be national champion for a seventh time."
Adderley, seen as Scottish squash's best prospect, said: "Coming into the event aged 16 as number one seed brought its own pressures.
"But I had played in this event last year for the first time and that helped me with nerves and what to expect out there.
"I played well in my semi-final on Saturday and that left me feeling good about the final.
"We had some really good rallies in the first game, but she then came back in the second. At that point I had to hold my nerve, but I did and got a good start to the third game. I then managed to go on and win and the feeling at the end was amazing."
The Scottish National Squash Championships at Edinburgh Sports Club is part of the Team Scotland Series which brings together 17 Scottish national championship events in 2017 across 12 Commonwealth Games sports.

The company says the new overhead compartments will allow passengers to store more hand luggage on its side.
The bins will be fitted to some 737 aircraft from the end of this year, the company said.
The new design will mean a 2in (5cm) reduction in headspace for passengers, it said, but air vent and light controls will be easier to reach.
The loss of headroom may be of some concern to taller passengers, some of whom already struggle with the amount of legroom in economy seating.
The new bins can be retrofitted to any of the "Next-Generation" 737s, of which 5,000 are currently in service.
Boeing says the balance of the bins has been shifted so they close without the need for a catch or the "bin assist mechanism" currently in use.
Travel writer Simon Calder told the BBC: "For the long-suffering passenger, this is mostly good news. By charging for luggage, the low-cost airlines have incentivised us to take everything on board.
"And guess what? There isn't enough room, so we've had to check in stuff at the gate.
"So this should help with that problem."
Boeing said the bins should speed up boarding and that "passengers will benefit from decreased anxiety about finding space for their carry-on bag when boarding a flight".
Alaska Airlines and Delta Air Airlines are the first two operators to place orders for the bins for their 737 fleets.

The weir, built as a permanent wooden structure to catch fish as the tide ebbed, was found by chance on the shore of Southampton Water in 2005.
Radiocarbon dating has shown it was built in the 8th or 9th centuries.
Experts from Exeter University said the results were "thrilling" and provided new insights into the process of coastal erosion in the area.
The 70m-long (500ft) structure was found by chance close to the Fawley oil refinery by archaeology students more than 10 years ago.
Tests showed the structure was built between 680AD and 896AD.
Marine archaeologist Dr John Cooper said the discovery has allowed historians to map changes to the shoreline over 1,000 years as it was covered by advancing saltmarsh which later retreated, gradually exposing the structure over the past century.
"It has highlighted the level of erosion in Southampton Water over the last few decades. There are factors like sea level rise and dredging carried out but it shows how dynamic coastal change is."
He said the wooden structures, once exposed are vulnerable to shipworm and are likely to continue erode away.
Some of the posts and wickerwork have already vanished since the initial find in 2005.
Edinburgh teenager Georgia Adderley won the Scottish women's squash title for the first time at the Senior National Championships on Sunday.
[NEXT_CONCEPT]
Boeing has shown off its "space bins" that can hold 50% more luggage than existing designs.
[NEXT_CONCEPT]
A timber fishing trap exposed on the Hampshire coast dates back to Saxon times, it has been confirmed.