Yann Fredericks boards the Hogwarts Express on Platform Nine and Three-quarters from King’s Cross for his first year at Hogwarts. He thinks that Albus Potter looks like his father Harry – until Albus is sorted into Slytherin house (CC1.4).
It is not stated whether Yann is sorted into Gryffindor or Slytherin House. However, he is probably a Gryffindor because later he is very upset when Albus loses points for Gryffindor House during Defense against the Dark Arts (CC2.11).
From the Web
Pottermore: Harry Potter and the Cursed Child
The theatre production opened in the West End of London at the Palace Theatre on 31 July 2016, with James Le Lacheur in the role of Yann Fredericks: Harry Potter and the Cursed Child, Parts One and Two