Hi Tom, no it doesn't mean you have killed it. 901 batteries are very sensitive, and often if a cart is overfilled or just a bit of
juice has seeped through from the atomiser, and this could be happening if you are hearing a sizzle, then it can get through to the battery causing it to send out this warning.
The 9 flash warning signifies the battery needs a charge, but as you rightly say, often this is not the case.
Three flashes usually means you have taken too long a draw, but the 901 being the 901 seems to just throw tantrams, but its still the best flavour e cig I have tried.
I no longer use a 901, but when I did, if I saw this, I would unscrew the battery and clean both the battery end and the atomiser connection, re-screw and start again.
If you know connections are clean and dry, simply unscrew and re screw, it should work again.
This could also signify a new battery is needed. Batteries have varying lifespans, in fact I still have my original two 901 batteries, but both my hubby and daughter have had to renew one.
Hope this helps a little.