Three different things people call a download
A movie file, a viewing app's offline copy and a Series9 list backup are different items. This site offers title browsing and text backup for saved choices. It does not provide movie files or a Series9 video downloader.
Want a film for a flight?
Find the film here, open the viewing choices and check the selected service's offline feature before travelling. Offline access can depend on the app, device, plan, title and remaining viewing time. Test the downloaded copy in that app before relying on it without a connection.
Keeping episode information
A saved Series9 checkpoint records the last completed season and episode in this browser. It is not an offline copy of that episode. A home-screen shortcut likewise opens the website; it does not prefetch a season or promise that pages are available without connectivity.
Backing up your shortlist
Go to My List, create backup text and copy it into a file you control. That text contains title identifiers and episode notes, not video data. Backup instructions show how to merge it into another browser without replacing existing progress.