Bro mine is the 'saadi wali' CL9 as far as features are concerned, so others can chime in with respect to that.
Transmission issue is the first thing that comes to mind. Should be no harsh shifts, funny sounds on gear change, etc. Some K24 engines had oil consumption issues straight out of the factory, but i haven't heard many cases here though. Then there are many variants of K24 and K20 so need to make sure you're getting the 'real' CL9 engine, which is K24A3. Other than these, I can't think of any pet CL problems. Just look for the usual stuff, as in any other car.
I am lucky because I have some good mechanics. This coupled with the fact that, in my experience, CL parts (both genuine and kabli) have pretty reasonable availability - means that one should be able to take good care of the car after purchase. Also, in my experience its parts are no more expensive than 8th Gen Civic or 10th Gen Civic, both of which I have kept.