Can you be held liable for charges without a bill?

There are a few things in your question that aren't quite clear, but it looks like your husband has a serious problem here.

If the judgment was entered five years ago, from the case when your husband went to court, he either left the courthouse before the case was finished, or did not follow up afterward to make sure that he was out of the picture.  In any case, the contract between your husband and his former roommate wasn't binding on the landlord, unless the landlord agreed to that in court -- and in writing.

When you say, "He did not move for 3 years," I'm assuming you're talking about your husband, and the fact that nobody came after him for the money after the court date.  That, unfortunately, isn't going to help him, because the lawsuit for unpaid rent is, itself, all the "bill" that he's entitled to.

The interest rate is 9% per year, not per month.  But the amount remaining due on the judgment, with that interest, will have to be paid before the judgment can be removed.

For more information, you should see a local attorney.  You can look for one here:  http://attorneypages.com

As a practical matter if they haven't already come after up to this point, they probably won't.  This, however, doesn't mean that you shouldn't try and get this paid. Even though they're not pusuing now they could in the future. 

In terms of your credit, negative information comes off in 7 years. You could wait it out for another 2 years (it's already been 5).  However, many times if you contact the credit bureaus (Equifax, Experian, TransUnion) and dispute this information they will check with the creditor; if the creditor doesn't respond within 30 days the credit agency must delete the information from your file. 

Of course, as I said, at some point this should be cleared up; if for nothing else interest is accruing.