anyone feel free to correct me if smarta$$ me talks bull$hit but here's my take anyway...
For example we're talking of Eneloops 800mAh AAA: then the very lowest you can get (e.g. after 850mAh discharged capacity) UNDER LOAD is 0.8V (~0.81-0.82V, typically it's more like 0.83V).
this is UNDER LOAD.
let this Eneloop cell rest for 2 3 hours, or 23 hours or whatever. the voltage will recover (but the cell is still empty of course!) to, say, 1.10V minimum. This voltage is called "resting voltage", "voltage at rest", or i call it "offline voltage (at rest)". Believe me, you will NEVER find an Eneloop at rest, which has your quoted "0.9V". At rest, the Eneloop (if it is 100.1% depleted) will have at least 1.10V.
What does the C9000 do? It discharges (slowly) down to 0.9000V (cell is maybe 95% empty by then) and then let it rest for 1 or 2 hours. during that time (e.g. the 2.0 hours) the cell recovers to 1.2000V (pretty much exact this number). In other words, a NiMH cell with 1.20V resting voltage is considered "empty" by the C9000. The truth is, it's possible to quench out even more capacity (with electronic gadgets or flashlights with superlow current draw) such that the resting voltage approaches the 1.10V. If you do this hardcore overdischarging too often, you probably hurt the Eneloop cell in some way ("aging") although i cant confirm this because Eneloop cells tolerate all kinds of abuse.
*If* you do find Eneloops at rest which show 0.80 or 0.90V on your DMM, then your DMM is either is kaput, or i will call you a liar haha or your the first Eneloop owner in the world who managed to produce such a resting voltage state, world-premiere!! (the probability that your Eneloop cell is broken and that be the reason why you get such an otherwise impossible DMM reading is practically zero because Eneloops are robust in many respects.)
In summary, if you know that your Eneloop cells are okay (not broken), then at discharged state (e.g. up to 850mAh discharged for Eneloop AAA) and at rest, you will never see 0.8, 0.9 or 1.0V. Never. 1.10V is the lowest you could measure. More typical voltages are between 1.16 and 1.20V; if your DMM reads 1.20V (at rest) or lower, then it's time (and not too late yet! :) ) to recharge the cell.
hope this helpz.