one ip is doing it, useless to put 9 more proxies that obviously are on the same server
You can put more than one IP address on a single server with no problem. As heiny pointed out, you just need to make sure they are in different C class networks. Better yet if you can get them in a different A or B class network.
heiny, one suggestion for you if you have not already implemented it is to setup reverse DNS with different hostnames for each class C.