Nonet can be used to refer to a group of 9.
Generically an ensemble is a group of things (usually but not always musicians). In music a ensemble can also be a:- duet, trio, quartet, quintet, sextet, septet, octet, nonet, etc.
The standard collective noun for 'musicians' is an orchestra of musicians, no matter how many make up the orchestra.A general word a group of nine (people or things) is a nonet, making your group a nonet of musicians.
The cast of Beogradski Nonet in Concert - 2000 includes: Beogradski Nonet as Group
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