IMO there were a lot of contextual complaints about the 009 that are no longer as relevant today:I also remember the 009 release very well. Plagued with driver imbalances - but the supply was low and it took a lot of people time to get theirs. People hailed them as being the most resolving headphones of all time, but they did not do as well at mini-meets where several found they preferred their 007/omega/he90.
-Channel imbalance QC disaster which is no longer of concern
-Price vs. 007, which is also no longer a concern, in fact some of the 007mk1s on here are priced higher than 009's
-It is 110% a titanic shift in FR from the 007, I think this affected a lot of its initial impressions, it is like giving people intimately used to Audeze a Beyerdynamic.
I disagree with the assertion that the 009 is overly bright, it is brighter than average but not troublingly so, however if you are used to the 007 it might as well be a Grado. I have no factual basis for this next comment (lol) but I think if you gave 10 listeners the 007 and the 009, and they had never heard either, the majority would say the 009 is more neutral than the 007. It skews less bright than the 007 skews dark.
I think the 009 will be vindicated in time and its reputation as a controversial headphone is undeserved for the most part. It is the apotheosis of that entire era of Stax and is the most stereotypically "electrostatic" headphone ever made imo, for better or worse.
Also to be clear I do mean specifically the 009 and not the 009S. I feel the same way about the 009S as the Senn 800S, sidegrade at best.