When you play your sequence on a soft seq you can get 127 different velocity's, other than 2 (accent and not accent). Not sure if 909 accent is only about velocity indeed. This way you can achieve delay (trough midi delay;try FL) of snares an hihats for example. You can even play both simultaneous (as I remember). You can leave the base on the 909 (kick and toms) and trigger the hihats and the other tones by the soft seq. Or just make a big mess.
Anyway, I recommend to use the 909 seq. Mayble sample delayed notes. But thats all... its sequencer may not be too flexible but thats not what it was made for.
Sorry for the bad English