The A9 is a very inexpensive device. It does everything, but rather slowly, with a mediocre display. Apart from the charging cable, I wouldn't want to connect anything to it.

This is probably not due to the reader, but to the card.
Not always easy, may be due to the formatting or the card type or size.
It should certainly be Fat32 or exFAT as the format.
Try it out or ask the Internet.