I'm confused.

9.1.2 refers to the departure time of the flight. The departure time has not changed for the OP: EK29 will continue to depart at 0940 Dubai time.

9.2.2 refers to "failing to operate the flight reasonably according to schedule". It makes no reference to aircraft type. If a B777 is substituted for an A380, but runs on time, then the flight has operated to schedule. If you are bumped down to Business from First Class because the plane doesn't have your class then you'd have an argument for a change or partial refund for the reduction in class. But if you bought and are allocated a Business Class seat on a B777 instead of an A380 and you arrive on time then you've got what you paid for.