I live in Halifax and make trips around the region on a frequent basis. September, IMO, is one of the best months to explore the area. The bulk of the tourist crowds are gone; the weather is warm during the day, typically without any humidity, and can be cool over night. As you get toward the end of Sept, you will find that some attractions and restaurants may be closed or have irregular hours (Cape Breton Cabot Trail area, smaller, seasonal shops along the Halifax waterfront).
Downtown Halifax is very hilly. From the waterfront up to the Citadel would be a hard slog for someone out of shape or with mobility issues. The Halifax waterfront is a great area to wander. Maritime Museum of the Atlantic is worth a visit - doubly so if you have an interest in the Titanic (if you are really into the Titanic, a section of the Fairview Lawns Cemetery, which is just outside the city core, was used for victims). For $2.75 per person (each way), take the Alderney Landing ferry across to Dartmouth and explore the downtown portion (Dartmouth and Halifax used to be separate cities but amalgamated a couple of decades ago along with Bedford, Lwr Sackville, and a pile of smaller communities.) Go to the upper deck for the most inexpensive harbour cruise you will ever find. Just note that our antiquated transit system requires exact change or payment using a convoluted (eg shitty) app. There is a $7 'day pass' option on the App which is ok value if you think you will us the bus in addition to over / back on the ferry.
The Harbour Hopper will give you a touristy trip around the downtown, with a short ride in the harbour. For me, I find that it is quite pricey, but it always seems to be packed so what do I know!
Halifax Citadel, Public Gardens, and Spring Garden Road area also worth a visit. I would drive from the waterfront area to the SGR area to avoid the walk up the hills (or jump on a bus from Barrington St area to SGR area)
Bay of Fundy area. Assuming you are going to stick to the NS side of the Bay? Grand Pre, which is an hour outside of Halifax, is a great stop. The area, which is a National Historic Site, is the epicentre of the Acadian expulsion in NS. If you continue down the road, you will eventually end up at a parking lot next to a camp ground. If the tide is out, you can go down a long staircase and walk along the beach.
From Grand Pre, travel 5 mins to the 'artsy' town of Wolfville. Very walkable little town. Good spot for a coffee. From here you can quickly get to the village of Canning, go to the Look Off, go to Blomingdon Provincial Park.
Halls Harbour, which is around 45 mins from Wolfville, is a small fishing village where you can see the effect of the tides on the fishing fleet. Low tide the boats are resting on the sea floor. Last month HH had some major damage to the main road due to a flash flood (
https://atlantic.ctvnews.ca/video/c2957013-halls-harbour-impacted-by-heavy-rain). It may be open by next month.
I think I've seen a few forum members from Cape Breton so hopefully they will chime in on the area (I'm guessing you are looking at the Cabot Trail area of the island).
Feel free to reach out if you want any specific info. If you are going to be in Halifax at the tail end of the month and want a tour guide for a few hours (or for the day), let me know. I'm going to be travelling in Newfoundland from the 1st to the 17th, but would be more than happy to show you around once I get home.
Cheers
