While KE has let me fly with an animal that weighed 6.6 kgs before without even weighing it, acceptance basically all depends on the agent you get at check-in. Nobody can guarantee you won't be turned away.
If it is crucial to get the cat in the cabin with you and you want to make sure it'll be accepted without trying to game the system, you will have to use one of the European airlines with a higher weight allowance (AF/KL/LH...) - but you will have to route the long way via Europe as AC (only North American airline allowing pets in the cabin on international flights, 10 kg weight limit) doesn't fly to MNL.
Check your PMs.