✔ 最佳答案
Let me try
For the first sentence, I think there is grammatical mistake, because
''I used to be a basketball player'' means that you were a basketball player but you are NOT a basketball player anymore
so, it should not be followed by ''and I still am''
For the second sentence, I think it's fine.
''I used to hate banana'' means you hated banana in the past but now you like it.
However, I think it can be rewrote as follow:
''I used to hate eating bananas, yet, I like it now.''
This sentence means you didn't like to eat bananas in the past but you like it now
Differ form the original one, which actually means you hate banana itself.
Both of them are grammatically correct, but their meanings are different, you can choose the one that expressed your meaning.
Feel free to point out any mistakes in my answer.