I asked Aisha about the night prayer of Messenger of Allah ﷺ and she said, "It was seven, nine or eleven rakʿat besides the two rakʿat of the Fajr prayer (i.e. Sunna). " (Using translation from Bukhārī 1139)
عَنْ صَلَاةِ رَسُولِ اللهِ ﷺ بِاللَّيْلِ؟ فَقَالَتْ «سَبْعٌ وَتِسْعٌ وَإِحْدَى عَشْرَةَ رَكْعَةً سِوَى رَكْعَتَيِ الْغَدَاةِ»