The hijackers were Saudi nationals, but the operation was in no way sponsored by the Saudi state, which is a staunch US ally. Which is why the US proceeded to (attempt to) flatten Afghanistan instead.
> the operation was in no way sponsored by the Saudi state,
We do not know this. There are plentiful evidence to suggest direct involvement of the state itself, and the bin Ladin family is certainly hard to untangle from the Saudi state. That is just from what we can know from unclassified sources.
The current Taliban are an almost completely different organization despite there being continuity from then to now. A good comparison point is the church of England in 1520 vs 1620.
We do not know this. There are plentiful evidence to suggest direct involvement of the state itself, and the bin Ladin family is certainly hard to untangle from the Saudi state. That is just from what we can know from unclassified sources.