Your questions about SoFi Hong Kong are answered here

Extended hours trading refers to trading US stocks outside of core trading hours (i.e. 9:30am – 4:00pm EST). Pre-market trading occurs before the core trading session and after-hours trading occurs after the core trading session.

Pre-market 4:00am – 9:30am EST

After-hours 4:00pm – 8:00pm EST

In the event of half day trading, the core trading session closes at 1:00pm EST and the after-hours trading ends at 5:00pm EST.