as the topic reads, does it come with aluminum pedals?
I would think a top of the line range should.
also would the OEM aluminum pedals fit all Mazda models?
it seems like all the pedals are standard across the whole range.
As Azeke stated, no aluminum pedals in any trim of the CX-9. Refer to my sig for a DIY pedal upgrade. Very easy, and aluminum pedals can be found pretty much anywhere for about $25 USD.
EDIT: Not sure about pedal covers from your 2014 3 fitting on the 18 CX-9, but I would take them off if you sell the car or trade it in. If they don't fit on the car you buy, throw em on craigslist or FB Marketplace, I'm sure someone will take them off your hands.