Is there any substitute for the processing solution/developer? I bought three shade colors and processing solution on ebay. I got a clear, totally liquid, water-like solution as the processing solution. I do not think this is what it is supposed to be like. Am I right? If so, is there anything that I can use instead?

Everywhere I read says the processing solution is supposed to be a creamy formula but this is literally like water. I'm really confused and I don't wanna ruin my hair. Just want to be clear that it's not the actual shades eq color I'm referring to but it is the processing solution/developer used with it. If I mix the one I got with the actual color which is also purely liquid in consistency, it would be a water-like mixture. Is this how it's supposed to be?

Also, I have light bleached blonde hair. It's not platinum but very light and neither too cool nor too warm, more like a natural blonde color but it is somewhat yellowish. I want a neutral (not too cool and not too warm) dark-medium blonde color. I bought 9gb, 9nb and 9n because I know the colors run dark but I'm thinking these may not deposit enough color. Can anyone advise me on what shade or mixture of shades to use? I would really, really appreciate it.