The figure is down from 10 flags awarded last year.
Beaches with a Blue Flag demonstrate their commitment to protecting the coastal environment, water quality, safety, and access for all.
Keep Northern Ireland Beautiful have presented beach and marina operators with 14 national and 10 internationally-recognised awards.
Two marinas have also been awarded blue flags - at Ballyronan, County Londonderry, and Ballycastle, County Antrim.
Tony Wilcox, chairman of Keep Northern Ireland Beautiful, said: "Having Northern Ireland's world class beaches managed to such high standards is helping improve the quality of our lives as well as attracting visitors".
Forty-seven countries participate in awarding Blue Flags to more than 4,000 beaches and marinas worldwide.
The Department of Agriculture, Environment and Rural Affairs monitors identified bathing waters on 20 occasions during the annual bathing season, which runs from the 1 June until 15 September.
In 2016, Portstewart Strand in County Londonderry was awarded the accolade of Best Blue Flag Beach in the UK.
County Down: Cranfield West, Murlough, Tyrella
County Antrim: Portrush West Strand, Portrush East Strand
County Londonderry: Portstewart, Benone, Downhill
Twelve beaches were given the Seaside Award - the national standard for beaches across the UK.
This award guarantees a clean, safe, attractive and well-managed coastal environment with varied levels of facilities provided depending on the location of the beach.
Two Northern Ireland beaches have received the Green Coast Award, which recognises an agreement with the local community to protect and promote a natural beach environment, rather than developing visitor infrastructure.
Eight Northern Ireland beaches will proudly display international Blue Flags this summer.