Kade Chandler's "season review" article confirms what most of us expected - he got a 2 year contract.
Doesn't explicitly state that he will move to the main list, but I'd imagine he has to. Pretty sure the maximum time as a rookie is 4 years, and this will take him through to year 5 on the list.
https://www.melbournefc.com.au/news/1028325/-21-season-kade-chandler