Depends on the Airline, in many cases the group rates start at 8 Passengers so 9 passengers would qualify.

In an interesting pricing point the group rate is often higher than the individual ticket pricing. Future.Travel will let you book 9 at the lowest fare available at the moment of booking. 90% of the time cheaper than a ‘group’ rate.

In some cases the airline systems force the booking of all seats for a booking into the same fare basis, eg 9 seats in G Fare basis as 9 seats are available, rather than 6 in L fare basis (lower cost) and 3 in G class (higher cost). Best to make the call to your agency before finalising a ticket purchase. You may find some hidden (by the pricing robots) savings when you interact with a human.