YOU SAID:

that cat sat in the bus waiting on their apponment

INTO JAPANESE

その猫はバスに座って約束を待っていました

BACK INTO ENGLISH

The cat was sitting on the bus waiting for an appointment.

INTO JAPANESE

猫はバスの中で座って約束を待っていました。

BACK INTO ENGLISH

The cat was sitting in the bus waiting for an appointment.

INTO JAPANESE

猫はバスの中で座って約束を待っていました。

BACK INTO ENGLISH

The cat was sitting in the bus waiting for an appointment.