Some references to the iPhone 9 were found in the first beta version of iOS 13.4.5, with lots of clues about the possible hardware features.
9to5Mac has found this information within the iOS 13.4.5 code released a couple of days ago. It turns out that the CarKey feature will allow to use iPhone and Apple Watch as digital keys to unlock and start a car. It will also be compatible with iPhone 9. It was not foregone news, since to date the CarKey APIs have referred to only for models with Face ID, while the next cheap iPhone will integrate only the Touch ID.
Also, CarKey will work in a similar way to Transit Express cards, therefore also with iPhone or Apple Watch with completely exhausted battery and without the need for authentication. The latter function is active only on iPhone XR and later models.
iOS 13.4.5 reveals however that there is an iPhone model with integrated Touch ID compatible with CarKey and Express Transit. Since the iPhone 8 does not have this combination of features, it is clear that it refers to the iPhone 9 or iPhone SE 2.
In another line of iOS 13.4.5 beta code, Apple added this message “Your device does not support the car key feature“, demonstrating that older iPhone models will not support the CarKey feature.
The iOS 14 code previously revealed that iPhone 9 will also be able to scan NFC tags in the background, an essential feature for CarKey and impossible to do with iPhone 8. Recall that the iPhone 9 could be announced on April 15th.