Eh, I have to agree with what other people here are generally saying about your situation.
First, as some others have said, I would definitely recommend getting a new doctor if I was you. I honestly have a pretty liberal doctor from what I hear, as I've never been drug tested, my dose is almost completely based upon what I ask for, he's experienced and understanding with opiate addiction, he takes as much time as he has to to talk about anything, even non sub related stuff, and he's usually pretty flexible when it comes to payments. I see him about once a month.
Anyways though, my point is that it's completely ridiculous that a sub doctor would make you take doses in front of him or wouldn't be cool with that kind of dose adjustment; the whole idea is that they do what they do and get paid in order to supplement the suboxone by talking to patients, making sure they're healthy, and not making life any harder. The fact that your doctor is not at all concerned about making you miserable, interfering with your schedule, or I'm guessing charging you money so he can police you, makes it obvious that he's an idiot that really doesn't respect you much as a patient, and that's wrong for any doctor, especially one that you're going to voluntarily for help. You should def. ditch him, especially if he supposedly cares about your dose and would have you taking that much for something like codeine.
Also, taking 9 mg of sub a day for codeine in pretty much any dose is pretty inappropriate. I got off a relatively heavy (for me at least) heroin habit of shooting .3-.6 g a day about 6 months ago, and I started at 8-12 mg sub a day, but it didn't take long for me to start rapidly lowering, and although the last time I used sub was about a week ago, I've been comfortably at doses of <1.5 mg for a long time.
See, there's reasoning for this in the sub mega thread, but here it is: TAKING LESS SUB GETS YOU MORE EFFECT. So saying you don't want to lower your dose of 9 mg a day cause you're chasing a high doesn't make a lot of sense. You'll get a lot more euphoria by lowering your dose.
Another thing, there's a ceiling dose to codeine I'm pretty sure, and even at that dose with any appreciable amount of sub in your system it isn't going to do much of anything at all. In case you weren't aware, codeine is probably one of the weakest opiates around (actually it isn't an opiate itself, your body converts it to morphine, but that another story).
Finally, about the H thing...the reason I haven't taken subs in about a week is due to the fact that I came into possession of some very high quality, almost free heroin (which I've just run out of actually. resuming subs tomorrow morning) and I'll say this from my own experience; unless you plan on taking a break from subs for a appreciable amount of time, it won't be worth it to take breaks.
I say this because in order to take another opiate and get worthwhile effects without shooting any large doses you would have to wait probably about 24 hours at least, so that means going without subs for a whole day which you said is an issue for you. Then you take your opiate of choice, and hopefully the suboxone won't still be an issue. Then, after you have your fun, you need to wait until you're in full on withdrawal/all the opiate is out of your system before taking subs again, cause if you don't, you'll get thrown into precipitated withdrawal, which I've heard is absolute hell. So in order to get high, we're talking some 32-40 hours in which you can't be taking subs.
That means it would be pretty much physically impossible to do it just on weekends, at least the way I see it (and I'm no expert).
This is assuming what I'm guessing will happen doesn't happen, cause what I'm guessing is if you get your kicks taking codeine, that when you try dope there ain't going to be any "only on the weekends" or "just every once in a while". Hell, the majority of relapses that turn back into terrible, ugly addictions start with the "every once in a while" line, and it happens easily enough to people who are veterans of heroin addiction and know exactly what to expect; so I mean no offense in this, but I'm almost positive just from how it sounds that you wouldn't stand much of a chance of keeping it from graduating into full blown addiction.