I am not aware of any fiddle concerts planned for September 5th and 6th. However, you might be interested in attending one of the ceilidhs being held on those dates. There is usually a fiddler on hand in those variety concerts held in small halls. Please check this website: www.ceilidhs.ca/pei-ceilidhs.html
If you happen to be in PEI on Labour Day weekend, you can attend the annual fiddling and stepdancing concert at the Acadian Festival (Exposition agricole et Festival acadien de la Région Évangéline) in Abram-Village on Sunday September 2, at 2:30 p.m. You will be treated to a great afternoon of traditional fiddle music and great stepdancing.
Check: www.expositionfestival.ca/ and www.corridorcanada.ca/province_tax/prince-edward-island/?lang=en#group-2
The main fiddling festivals on the Island are held in July and August. For more information, check the Prince Edward Island Fiddlers' Society: www.peifiddlers.com/events.htm