There are a few products out there in the market that will help you remedy the situation. Ebtech make the HumX, which many people seem to like because it gets rid of their noise. The next would be the Boss NS-2, which basically takes the dirty signal and attemps to clean it up. Although, this is a great pedal and many people swear by it, you really want to attack the noise at its source, and that is the electrical current. Ideally, you really want to run a nice line conditioner, so it prevents ground noise from filtering through the pedals. So, a nice power strip or rack mounted power supply will do the trick. Monster has the power pro bar (1000 and 2000), which has built-in filters that reduce noise and give you a cleaner signal.
Unfortunately, any time you have noise and you're trying to get rid of it you're going to wind up spending some money to achieve this. Keep in mind that noise is introduced in a number of ways and through several paths, so your power conditioners/line filters will take care of some of the problem but not completely. Cables can affect your signal, specially when you're using smaller cables to go in and out of effects boxes and joining them together.
I would discontinue the usage of those 9v adapter with the extra leads you soldered to them. The main reason why is because it is more likely that the leads are introducing more noise to your pedals than anything else. If some of your pedals came with power supplies, I would use them. If they are bulky, use a big power strip like the one I described above.
While I'm not encouraging you to spend money on monester products, I'm simply letting you know what's worked for me. Having spent at least a couple of thousand cables and power conditioners alone for my home theather, I can tell you it makes a difference.