Mark, I'm not sure that you will get a completely straight answer from anybody. Diamox works, but it depends.
First of all, you might try to explain your symptoms when you get above 9000 feet. Then you might want to decide if there is some very ordinary reason involved besides altitude. In my experience, about 80% of the symptoms that are experienced are a result of dehydration. Some people seem to feel bad, but it turns out to be a result of working too hard carrying a heavy backpack, and it has little to do with altitude. One guy used to get bad headaches at altitude, but then he discovered that it was from lack of sunglasses, and the extreme UV light was doing it through his eyeballs.
I admit that I have carried Diamox on three occasions, and I have actually consumed it on only one occasion. The side effects are well-documented, and some people claim that they vary with dosage, so some people try to keep their dosage minimized. I experienced those side effects exactly as documented. One guy I know eats the stuff like it was candy (several times the recommended dosage).
Diamox is a carbonic anhydrase inhibitor. It is easier to think that it simply changes your water balance and your blood chemistry.
Decades ago, there were one or two other drugs that competed with Diamox, and I don't think that those are widely accepted anymore. Diamox is not always well-understood by every physician, so you might need to bring references when you request a prescription. On the first time that I requested Diamox, the physician asked me if I had congestive heart disease. Uh, no. Then he looked it up online and saw that it was recommended for altitude also. Then he asked me if I was allergic to any sulfa drugs. Uh, no. Then more and more questions. It is not exactly the sort of prescription drug that you want to take for fun. On the other hand, it has few serious negatives, and it seems to have a beneficial effect on a large percentage of those who take it for altitude. Some people claim that they get sick with or without it. It doesn't seem to be a foolproof preventative for all forms of altitude illness, but rather it seems to give you a wider safety margin compared to going without it. There are several ways that you can screw it up, so you want to speak to your physician about this.