ex-UK, T fares have a 21 day AP requirement. I think E is 7 days and then after that it's W only.

ex-EU last I checked T was typically 7 days AP.

(For that reason, your flight might well be T9 but if you're inside the 21 days, you won't be able to buy it at the T fare ex-UK).

You can check out the specific fare rules on EF for your route(s).