Support Python 3.14 & Drop 3.9

[leofang]

[cpcloud]

Let's wait until 3.14 is released before doing the work.

[cpcloud]

Since we have 3.14rc builds, and 3.9 is on the way out, I'm going to PR the 3.9 drop, and we can merge it after the upcoming release.

[leofang]

yes I've added a FutureWarning raised at import time to cuda.core PY39 users in #1041, we should do the same in cuda-bindings too