Sorry to have to say this (yet again) but I would bin that bloody thing before it explodes or burns your house down. We've had report after report after report about them failing. When it says "NEVER LEAVE CHARGER UNATTENDED WHILE IN USE" it really means it.
A 2A charger should charge a 1.6Ah battery in under an hour. If it's been shoving current in for 9 hours it's been cooking it.
However, I'd hazard a guess that the battery is fully charged, but that the charger can't recognise that. Nimh is a bit of a sod to charge. The charger doesn't know what voltage the battery is meant to be, all it can do is to shove current in until it detects the battery resistance rising sharply when it's full. If it fails to spot that rise happening, it's liable to just keep pumping energy in indefinitely.
If you stick with it, only use it for under an hour, and disconnect it if the battery start to heat up. Or take the plunge and get yourself onto better technology.
Lipo cells are really cheap now (see HobbyKing) and can deliver higher current in a smaller package. You'll not see much difference between a 7.4V lipo and a 9.6V nimh.
On chargers, we're liking the SkyRC S65 or the IDST Q6 nano at the moment.