The best 909 / 808 clone I found so far is Audiorealism ADM. Never used it, but once made lot of comparison tests, though I did not test for exact original device behaviour, but instead for the best sound. Imo ADM sounds better than original 
adm is nice , but I disagree when it comes to the emulating part .
D16 drumazon is the closest , the 909 is almost spot on …
Also , renoise is fantastic …create a long dc sample’ 88200 samples ) , process track fx set to highpass and resonance , choose freq.cut of and process fx …a nice self oscilating sine …+small pitch env…
Then ad a single cycle transient ( nonlooped ) and mix it with the above …add a bit of noise …et voila …