Not sure i understand your issue exactly. The cruise control is suppose to slow you down fairly slowly, without the big red brake warning light, unless traffic in front of you stopped really abruptly. What year is your CX-9? Earlier CX-9 where known to have their emergency braking system a bit too nervous, but it still shouldn't engage regularly when using cruise control.
Basically, radar cruise control is supposed to slow you down progressively, emergency braking system/avoidance collision system is to prevent accidents and brakes really hard. It shouldn't be relied on for as a cruise control substitute. Is the situation you are experiencing when using cruise control or when the emergency braking system comes on ? (big red BRAKE!! symbol)
Seriously? "Supposed to"?
Where does it say what any of this junk is "supposed" to do?
...more problems resulting from half-assed automotive automation. 'Supposed' to slow you down gradually...great idea in concept and theory, until, another vehicle cuts you off diving into your radar's 2-3 vehicle distance gap at 70mph. A simple thing like turning on the brake lights when the brakes are applied is a pretty basic automation concept and an epic design miss/fail right there if proven they do not illuminate. But as I've preached elsewhere on this forum, as well as others, the current crop of automotive automation idiots have a lot to learn.
There are far too many circumstances that would dictate the rate at which a vehicle on unpredictable non-standard public roads would need to stop. I've programmed AGVs on closed circuit courses and even at that, the challenges and what-ifs are numerous and must all be accounted for in order to obtain both safe and reliable operation. Try thinking about if you were the guy programming the braking system, in a car, on roads, in all types of conditions that you have zero control over and can't predict This is assuming of course the proper sensing hardware was in place to provide the critical feedback required to do so (which the crap in these cars is absolutely not). Think about this while you are actually driving, one simple trip and how you would deal with each and every situation that required your foot to work the pedal and how quickly and forcefully it worked the pedal. COUNTLESS scenarios requiring a crap-ton of exception handling programming (again, assuming the correct hardware is in place, which isn't because there's not enough money on the planet). Since I've turned all of this half-baked crap off in my CX5, I no longer have the thing incessantly beeping at me for no
good reason, and most importantly, have not nearly been rear-ended at all because of illogical, sudden high-rate slow downs or stops. I do use the RACC quite often but I am fully aware of its limitations...ie, I assume it can not stop me when it needs to and/or that it will slow me suddenly and too rapidly, or stop me completely, when it really shouldn't.
Consumers have to stop believing the technology in these cars is flawless...it's a far cry from it. In my world this stuff is barely prototype level and it certainly would not be deployed for mainstream utilization. What it is...is marketing gimmics. Merely listen to
any automotive TV commercial. Tech tech tech...tell them what they want to here...build it, and they will come!