The edge you have there looks better. Did you use the exact same endmill, or a fresh one? Take a look at the endmill UNDER MAGNIFICIATION (a 10x loupe is fine) and look for chips or welding.
The exact type of aluminum does make a difference, but the stuff carbide sells is considered "machinable" and should be fine with the feeds+speeds above. The number of flutes will change the engagement per tooth at the same feed rates. I would recommend fewer flutes before more flutes.....but it also requires computing the feeds+speeds. 9200 vs 10k rpm isn't going to make much difference.
You can cut dry, but I wouldn't try it with an uncoated endmill and expect a great finish. The important thing is to keep the chips out of the cut. I use continuous compressed air for this on my nomad, vacuum doesn't work well enough.
My (bad) notes to myself say:
.125 end mill, "chinese" - aluminum
Depth 0.0153, stepover 0.035, feed 4.5 in/min, plunge 1.5 in/min