The New York Post story was the first one to break this, its worth reading that one again and noting the multiple links to the Saudi government.Sorry but your article from Qatari news is rather short of details. It clearly states two Saudis who happened to be be low level government employees attempted to storm a cockpit but far from shows it was a Saudi government plot. And yes, some in Saudi were no doubt involved in terror attacks including 9/11 but that doesn't mean it was a government plot.
https://nypost.com/2017/09/09/saudi-government-allegedly-funded-a-dry-run-for-911/
The people who planned the attack were Saudi and were funded by the Saudis, not by the Taliban.As for Afghanistan, the actual people who planned the attack were based in Afghanistan with the backing of the Taliban government. It makes sense as a target.