You have a few options. The problem is the timing with many pubs not yet open. It also matters whether you want to just watch the game, or watch it with people.
Our shitty Casino is, well it's a casino, but they have huge screens and it will be on, and It's very convenient to your cruise location.
https://www.star.com.au/sydney/
The venue that used to host Hockey Night in Sydney (a bunch of Canadians ran it) has closed, but stunningly for you has just re-opened AT THE OVERSEAS PASSENGER TERMINAL two weeks ago meaning you literally have to walk 100m.
https://www.jamessquire.com.au/brewhouses/the-squires-landing/about-us/
There are a million tourist pubs in the area; they all have tvs but some won't change the channel because they're too themed or touristy or don't have tvs. Many don't have tvs. They're usuaully the best pubs. Others will. The Paragon is very close and will quiet enough you'll get a tv:
http://www.hotelparagon.com.au/
Further up George St into the city itself, and this is 5 min taxi trip for less than 10 bucks, is the best sports bar, Cheers Bar. It's the home of the Celtic FC Supporters Club, they have lots of tvs and will change to whatever you want, as long as there is no Champions League football which might be an issue on thursday morning now that I think about it... actually I looked and they show that they won't be showing it.
http://cheersbar.com.au/live-sport/
Your real issue is that the NBA Playoffs are on and everyone's going to be showing them. NHL isn't a big ticket here, and the NBA is, especially the Cavs.
I would go to the Casino after checking with the Squire brewhouse.