If they think you're going to help the team more than others, you'll be there regardless of size.
Guys like Point and Stankoven are/were smaller than guys like Cristalli and Heidt, they were just deemed to be better fits and help the teams out more. They were also much better/more complete players by a pretty sizable amount. That's not to say HC is always correct, they certainly aren't, but Cristali was not going to be a go to guy, they likely felt they'd rather have size. speed and physical play from their 9-13 guys rather than what Cristali brings.
Of course there is more lienency in junior, the WJ's are definitely more viable for small guys compared to the NHL
It's not like Cristali is an unknown to HC, they have been following and paying attention to him since he was 13 with St. George's.