Here's an alternate:
Take the A87 west until you pick up the A82 south toward Fort William and Spean Bridge. If you feel like exploring taking the small side rode west along the shore of Glen Garry before joint the A82. It's a beautiful Loch. The road is at the foot of the big hill that take the A87 to the A82. There are some walks out at the end--old drover roads I believe, but I mostly just loved the views.
As you near Spean Bridge there is a monument to the Commandos of WWII. Pull over and recognize their contribution and enjoy the scenery and views of Ben Nevis. This is where they trained before going to Europe to fight the Nazis.
As you approach Spean Bridge, look for the A86 which you take East toward Kingussie. You'll pass one of the many water power projects that make Loch Laggan. You can take the A889 to Dalwhinnie or if you are a Monarch of the Glen fan, continue north to Newton More. Some of the shown was filmed there. The view of the house that was used is near Kinlochlaggan.
Head sound on the A9. Watch yourself, it's a busy road with speed cameras coming. I'm not sure when they are turning them on, but there have been stories of average speeds being checked. Do stop at Queenview and take in the view and have a cuppa.
When you get to Birnam, this would be a good place to have a walk. There are several and they can long or short. The TI in Dunkeld will have maps if you want them. I love the walks in that area. Perthshire is lovely.
You can hop back on the A9 and be in Edinburgh in about an hour an a half.
Another area to stop and walk would be Pitlochry. It's a bit north of Dunkeld so a bit longer into Edinburgh. I've not done any in the area, but Kingussie has some as well. If you've not found this website, it's a good one for giving you some walks.