I've had a couple of 1009's pass through my hands over the years. The first one came with a Pickering XV15 with a D350 stylus, which was a .7mil conical rated for 1-3g. I wouldn't be surprised if that was the original cartridge. The second one didn't come with a cartridge, so I threw an Audio Technica AT-VM95C on it, which has a .6mil conical rated for 2g. Both sounded pretty good to my ears! I wouldn't hesitate to run any decent medium-compliance conical or fat elliptical on a 1009, but I'd probably avoid anything too high-compliance or exotic due to the fixed anti-skate and alignment.
I never quite appreciated this factoid about the Dual 10xx series until I picked up a Garrard Type A and tried like hell to make it work reliably with modern cartridges. Anything under 3g and the darn thing would either hang up or not trip towards the end of the record, no matter how much I tweaked it or fiddled with it. I'm sure the Garrard was a fine table in it's day, but the Dual must have been like a small miracle.