The script open only 9 sessions because the constant MAX = 9 and the for loop increments until i < MAX.

/ Test prepared by Nathan Pocock; compliance@opcfoundation.org
Description: Creates 10 concurrent sessions. /

function createSession561002() {
const MAX=9;
var sessions = [];
// create the session objects
for( var i=0; i<MAX; i++ ) {
var session = SessionCreator.Connect();
if( session.result ) {
sessions.push( session );
}
else {
break;
}
}

// now to close
for( var i=0; i<sessions.length; i++ ) { 
    SessionCreator.Disconnect( sessions[i] );
}//for i...
return( true );

}

Test.Execute( { Procedure: createSession561002 } );