Updated two different MAC's to Xcode 9.0 this morning and none of the new simulators are visible in preferences on either machine.
Tried the below to add them and no iOS 11.0 simulators available.
Window > Devices and Simlators
Click on the + button at the bottom left corner
Choose 'Device Type': 'iPhone SE'
Then 'OS Version': 'iOS 11.0' not in list
Anyone have any suggestions?