Compared to dogs, cats have a few advantages. In particular, they are more agile and stealthier. They may climb trees, and jump roofs. They are good navigating unfamiliar terrain and have a great night vision (Well, dogs have some of that night vision too, and better sense of smell, and they are more obedient).
Aside from boosting morale as a pet... one particular case where cats are useful, is in survival situations. For example Crimea Tom helped British soldiers to find food and clean water.
Additionally, cats can predict earthquakes... well; research is not conclusive on that. But at least Faith saved her owner’s life on the The London Blitz.
Another advantage of cats is that the enemy will dismiss them. For example, if the soldiers think they found an enemy in a trench but they only see a cat, they will think it was a mistake. Like it happened with Pitoutchi who saved the life of his owner in a trench in World War I.
However, cats are not good if you want to use them for assault. For example, attaching bombs to cats and sending to attack the enemy, or throwing them from a plane is a bad idea.
Wait, those links are about real cats. Certainly, these cats are better.
With the intelligence of a 10-years-old human, they can follow simple orders and you can teach them. Teach then to recognize threats. Teach them to understand tactical situations.
Well, they cannot really operate a weapon. You can strap some equipment to them, perhaps some armor. We can augment them with robotics, so we can have remote video feed and perhaps the ability to talk to the cat and drop a device. They would operate as a cheap, smart and stealthy land drone.
You may try to use them as a biological vector of attack, if you can make them carriers (preferably, biological carriers, but it could be just carriers of some device) of a biological weapon, they will be effective.
You may also drop explosives, hidden cameras and microphones, you may equip them with antennas to relay radio communications, and you can use them to do covert operations.
You could use them for sabotage, for example disconnecting the electricity, or with the explosives mentioned before. They may also misdirect the enemy by creating a distraction... the soldiers go to see what's over there and only find a cat, meanwhile your troops can roll in.
In addition, if you find a keyboard, the cat can jump on it... In fact, if they can play the piano, they may type some commands. Or you can hack the wireless network with device mounted on the cat, whatever works.
If you need them to face soldiers directly, you would want numbers, many cats, swarm the place. Although these cats are rare and expensive, so it is better not risking them, so I suggest keeping them hidden.