L9不可以用普通地铁票，也不可以用T10 https://www.barcelona-tourist-guide.com/en/faq/airport/transport/metro/metro-to-barcelona-airport.html Airport Metro Ticket PriceThe cost for a single Airport metro ticket is €4.50 . Note that you cannot use a standard single metro ticket to go to the airport. You also cannot use the T10 ticket for the metro stops at Barcelona Airport. When you arrive at Barcelona Airport T1 or T2 you will need to validate your ticket in order to exit. If you do not have a valid airport ticket you will need to buy one at the Airport.
https://www.barcelona-tourist-guide.com/en/faq/airport/transport/metro/metro-to-barcelona-airport.html
Airport Metro Ticket PriceThe cost for a single Airport metro ticket is €4.50 . Note that you cannot use a standard single metro ticket to go to the airport. You also cannot use the T10 ticket for the metro stops at Barcelona Airport.
When you arrive at Barcelona Airport T1 or T2 you will need to validate your ticket in order to exit. If you do not have a valid airport ticket you will need to buy one at the Airport.
去T2坐火车应该还是可以用T10的。