Peutos Ksuvos 70a

Gemara ksuvos 70a "peutos" and rashi says בני תשע ושמונה. The question is that the gemara in gittin brings a few different opinions and no one says 8 and 9. Either ; (a) 6-7 (b)7-8 (c) 9-10. Also what's interesting is that rashi writes 9 and then 8. In gittin 65a rashi writes ״כבר שית כבר תמני״ which means 6 or 8 which is also interesting like we previously asked. Look in rashash there. Maybe someone can shed light into this.