Chris can correct me if I'm wrong, but Suunto will likely not accept a second-hand computer for return or repair. I replace the batteries by myself, and it is not actually that difficult. Using a standard watch back removal tool (I purchased from ebay), it is possible to remove and replace the battery, checking the o-ring. I accept liability for doing this, and if you do, you will have to as well.
What I'm curious about Chris, is if Suunto accepts liability for a computer that floods after Suunto has changed the battery. If not, the only reason to send to Suunto for battery replacement is the comfort that it has been done "correctly".
While I really like the D9, once it goes, it will not be replaced by another Suunto product.