Hi,
I don’t know how booking.com works, but yes the extension allows two-way sync. It can import an iCalendar file (or multiple files) for each room. And it creates an always updated iCalendar file for each room.
So, first you need to check if booking.com offers a public iCal URL for each of your rooms. If yes, you can paste that URL to the room’s settings and WP Hotelier will import the reservation of that room from booking.com every 15 minutes. Every room has its own iCalendar file.
Then you need to check if booking.com allows the import of external iCal files. If yes, in the booking.com settings you can use the exported iCal URL (one for each room) of WP Hotelier. And this will import Easy WP Hotelier reservation to booking.com.
Airbnb works in that way. Again, I don’t know if booking.com allows that. Be sure to check that before to buy the extension.