Your dog and your cats were fine at 6 months old. Now the cats are behind the sofa, your dog is following them room to room, and nobody in the house is relaxed.
The cats come first
Before any training, the cats need a house they can cross without meeting your dog. That is not a compromise. It is the condition that makes everything below possible.
Put a gate across one doorway, raised 4 inches off the floor or fitted with a cat flap. The cats pass, your dog does not.
Move food, water and litter trays somewhere your dog cannot reach, upstairs or behind that gate.
Add high routes in the rooms the cats use: a shelf, a wardrobe top, a cat tree. A cat with an exit stops running.
Do not let a chase run its course. One completed chase is worth 20 sessions to your dog.
Why this got worse at 10 months
Two ordinary things changed. Your dog is now fast enough to catch a cat, and the chase has become worth doing for its own sake. Responsiveness to your cues also drops around the onset of adolescence.
Chasing pays for itself, too. The cat leaves every single time, so from your dog's side the behaviour works, whatever you call across the room.
Tonight, 5 minutes, on a leash indoors
Put a leash on your dog and sit down 15 feet from a resting cat. Hold the leash without tightening it.
Each time your dog looks at the cat and then back at you, feed 1 piece of food. Say nothing else at all.
If your dog cannot take the food, you are too close. Move back until they can eat, because that distance is the condition for any learning here.
Stop at 5 minutes and leave the room with your dog. End it while it is still going well.
Do that once a day for 2 weeks. You are teaching your dog that a cat in the room predicts food from you, rather than a game.
Give your dog somewhere else to be
A mat in the same room, 10 feet off the cats' route. Pay it with a piece of food every 10 seconds while your dog lies there.
A chew at the times the cats move most, which is usually first thing in the morning and at dusk.
A leash on indoors during the busy hours for the next fortnight, so a chase cannot start while you are cooking.
Do not shout, spray or grab your dog for going after a cat. Punishment-based approaches are associated with fear and avoidance, and a worried dog near a cat is a worse situation rather than a better one.
Safety note
Get help now if your dog has caught, shaken or injured a cat, or if anyone has been bitten. Keep them separated from now on. That needs a veterinary examination for the cat and a qualified behaviour professional for the dog. The same applies if the pursuit is silent and hard rather than bouncy.
How long this takes
Expect a few weeks of gated peace before you see much change, then slow progress across the second half of adolescence. Some dogs and cats end up sharing a sofa. Others end up ignoring each other across a room, which is a good outcome.
Tonight's version, in one line: one gate the cats can pass and your dog cannot, and 5 minutes of paid looking on a leash.