Hi,
The device number description is presented in
https://www.nxp.com/docs/en/data-sheet/MC9S12XEP100RMV1.pdf
Appendix F Ordering Information
MC9S12 is automotive as well as industrial specified. When you order such a device you can receive a device with any mask set which is currently on the stock as well as the device labeled as S9S12 can be delivered.
Mask set defines errata list so in automotive industry parts MC9S12 are not so often used because all possible errata for all mask existing mask set should be considered in the application SW.
S9S12 is also automotive and industrial but now the mask set is a part of the device number so if you order it you will get exact mask set. For example, the mask set code is F1 in the device number S912XEQ384F1CAG.
F1 means mask set revision 1 of the mask M12S. (1M12S)
So, if you get a part with following numbers printed on top: MC9S12XEQ384CAG 1M12S
the it is absolutely the same as S912XEQ384F1CAG.
The errata list you should use is https://www.nxp.com/docs/en/errata/MSE9S12XEQ512_1M12S.htm
(errata set is presented at https://www.nxp.com/products/processors-and-microcontrollers/additional-mpu-mcus-architectures/16-bi...)
Longevity is defined for entire family S12XE without MC9S12/S9S12 differentiation.
(https://www.nxp.com/products/product-information/product-longevity:PRDCT_LONGEVITY_HM#products1)
Best regards,
Ladislav
