I would suggest that you get off the A9 at the Queens View and drive west toward the Lochs. It's the B8019. You can take the B846 in Tummel Bridge south to Aberfeldy. Or you can drive further west to Dunalestair. Turn left before you get to Loch Dunalestair to the south side and you'll find a small single track road that will take you through some gorgeous scenery toward Aberfeldy. The road joins up with the B846. You can continue on the B846 into Aberfeldy or you can turn west again at Keltneyburn and explore Glen Lyon. I think it's at Fortingall that you'll find the oldest yew. There was a nice gallery a few years ago. The Glen is really beautiful. You can turn around and head back toward Aberfeldy or continue on to the reservoir and head south toward Killin and back down toward Stirling and Edinburgh.
If you head in toward Aberfeldy, you can head west toward Loch Tay on the south bank and visit the Cranog Center, or stop and take the Birk's of Aberfeldy hike. Ailean Craigh on the north side of Aberfeldy had great food. You can head back to the A9 on the A827 or head south on the A826 to the A822 and Crieff and further south to catch the M8 back to Edinburgh.
Pam