Sunan an-Nasa'i
It was narrated that Abu 'Ubaidah said: "Aishah said: 'The Messenger of Allah (ﷺ) married me when I was nine and I lived with him for nine years.'"
أَخْبَرَنَا قُتَيْبَةُ، قَالَ حَدَّثَنَا عَبْثَرٌ، عَنْ مُطَرِّفٍ، عَنْ أَبِي إِسْحَاقَ، عَنْ أَبِي عُبَيْدَةَ، قَالَ قَالَتْ عَائِشَةُ تَزَوَّجَنِي رَسُولُ اللَّهِ صلى الله عليه وسلم لِتِسْعِ سِنِينَ وَصَحِبْتُهُ تِسْعًا .
Grade: sahih (Darussalam)
Reference