You have a few realistic options:
Human with cat ears, but human shaped skull
This would cause the ears to be placed on the side of the head, an odd placement for "cat-like" ears, even if the ears are shaped the same as a cats. As most humans are still capable of moving their ears a little bit, you would simply need slightly more developed and perhaps better placed muscles in order to achieve the similar range of motion. (I wasn't able to move my ears when in elementary school until I met someone who could, and I actually spent a few months training myself until I could move my ears too. I still can to this day.)
Human with cat ears, minimally modified skull
Moving the ears to the top of the head, while otherwise retaining human characteristics, would require some alterations in brain shape, skull shape, and moving the connections between the ear and brain to the appropriate location. This may cause interesting side-effects.
This would start with the cat physiology, and modify it just enough to be a true humanoid, ala TMNT bio-energy points. One consideration would be the spine and pelvis. The spine in a cat has muscles running along the vertebrae, which allows for the incredible twisting motions cats usually display in mid-air, or when contortion-snuggling. If the pelvis was altered to be 'locking' like a humans, then they would have an easier time standing upright, however lose some flexibility. If it was not altered, then they retain the full flexibility, but would get tired of standing up for long periods of time.
However, you would have the head and ears without any further alterations.
Tails shouldn't be too much of a stretch, either way. Humans are occasionally born with actual tails, a well documented phenomenon. The catch would be that a human tail wouldn't be very mobile, as it would lack the extra muscles alone the spine (and tail) that a cat has. Perhaps a hybrid musculature, or the anthro-cat style would work best.
Cats are "sprint-sleepers", a term which here means that they take short sleeps, interspersed by periods of wakefullness. During the day, the sleeping periods are longer, and the active periods are shorter. During the night, being nocturnal in general, they are mostly awake, with only short periods of rest or sleep.
This would lend towards nocturnal jobs more than day jobs, unless said jobs are intermittent or sporadic in nature.
The reflective retina grants better low-light vision, though it can be used to spot them in the dark as well, again lending towards jobs during the night or low-light conditions.
Cat's claws allow them to climb up things easily, but not down, due to the shape and attachment points; hence the cat-stuck-in-the-tree stereotype. Jobs requiring climbing might be applicable, so long as there is an alternate method of getting down.
Acrobatics in general seem a good fit, and anything requiring flexibility, balance, and a lack of fear of heights.
It is true that the whiskers allow for a more precise sense of if an opening is large enough for the head or not, so underground work is also not out of the question.
Heightened sense of smell (at least compared to a standard human, due to the vestial vomeronasal organ in humans which is still fully developed in cats) is a possibility. This is also why cats will make that odd, almost hissing-looking face when they smell some things, so as to allow air to pass over said organ. Wine-tester, food-tester (poison-tester?), artificial-scent tester, air-tester, and so forth might all be possible positions.