Hi & thanks for using our service. I'll do my best to give you a complete & accurate answer. Please ask me to clarify anything you don't understand.
If you mean "this year" is 2009, then no. If you bought & installed the water heater in 2010, then the 30% energy credit will be available in 2010.
Very very unlikely. The law as it exists is written for 2009 & 2010. Even if there was a change, the chances of it being retroactive to the beginning of 2010 are just about nil, or less than nil. It is more likely that it would be extended.
See the link which follows for additional assurance:
Not the link I intended but it actually has better data. Info also at www.IRS.gov