I was on the Carnival Dream in December and I did a test using the premium package. I was able to connect to our VPN(Using Global Protect). There was a lot a latency so if you using remote desktop like connections so it may be a little frustrating at times.
On a side note one issue I did have is our VPN uses a Two factor authentication application on my phone that also requires internet(in addition to my laptop) to work. To get around this I used the hotspot on my phone to share my premium plan with my laptop so I had a connection on both devices. After I figured this out I also let my wife use my hotspot connection as well.