Given the 9000 is on 65 profile tyres (which are positively 'balloonish' from a performance perspective) when specced with 15" wheels, I'd strongly advise going to a 16" wheel. The nearest 15" size you are likely to find some 'high performance' tyres in is 215/55 (coincidentally worn as OE fitment by some 'modern' 9-5 and 9-3 versions) - but I'm almost 100% sure your wheels are only 6" wide, which makes for a less than happy marriage. That, and I'm not sure 215 mm wide tyres would clear the fenderwells with the 'Anniversary' style flares at all times.
I'd go with 205/55/16 on Aero or similar wheels -typical performance favourites in that size are Bridgestone S-03 PP's or Toyo T1-S's. A slightly 'softer' alternative in terms of ride comfort and being geared towards safe all-round behaviour rather than pinpoint precision would be the venerable Dunlop SP-9000. Others to be considered are Goodyear's Eagle GS-D3 or the latest version of Michelin's Pilot Sport (although I'm not sure about whether they have that particular size, just having updated the tread design and compound - even BMW's new M3 CSL, when specced with 'normal' tyres rather than the Pilot Cup trackday specials,still wears the older Sports which, according to some here, have less than desirable wet weather characteristics).
If you go for 16" Wheels you can get 205/55/R16 W on Michelin Pilot Premacy which I believe may have been the OE on my Aero (1997). I'm not sure how the Premacy shapes up in comparison with the Sport though. Another tyre I keep hearing good things about is the Bridgestone S03.