1990 Civic SI CEL code 9?

Lately I have been getting a CEL code 9, No 1 Cylinder Position code. It happens in the morning, before I go to work. It goes on when I put my car into gear and go about 3 feet. If I warm the car up for 5 minutes, it does not go on. I have changed the distributor 3 times, with a used one and a brand new one. Same problem. I checked the wiring, via the Honda manual and the distributor is good and the wiring at the ECU is in the acceptable range using my multimeter. I took it into a repair shop and they checked for vacuum leaks and timing, and they said it was good and recommended that I replace the ECU. I swapped in an ECU from another working Civic SI and it is doing the same exact thing. The car drives fine while the check engine light is on, but it scares me to commute 40 miles to work. It does not go off in the afternoon when the weather is warm. I did notice that my car is rattling a lot, which kind of started around the same time as my issue. Yesterday I changed the oil and while I was under the car I knocked on the catalytic converter. It rattled a lot, and I see that this is what is causing my rattling. I banged on it a lot just to see if it was internal or the heat shield. I believe it is internal. Today when I started the car, the check engine light came on immediately and even after warming up the car and driving it down the block, the CEL would not turn off. The Code 9 was still the only code blinking. Could my catalytic converter be causing my problem?

1st of all, check engine light codes are more than one numeral, so whatever code reader you are using is not reading the correct code… Before you toss away any more $$, get the right codes, and look at the website: http://www.obd-codes.com/, and see exactly what the codes are for and what needs to be repaired

Thank you for the answers. Liverhuyen2003, my car is FI, fuel injected. The manual that I have is the factory service manual that the service technicians used. I went through the steps that are listed to troubleshoot code 9, used a multimeter and checked the distributor wires, which were in the acceptable range. I then checked the wires at the ECU, C1 and C2, I believe, and they also were within range. It is strange to me that I only get the CEL in the early morning. If I turn it on in the afternoon, the CEL does not come on.