I am planning out a Horror Short Film for youtube. Since youtube will compress the audio and video quality. Is it better to record the audio and sound effects at 48k/24bit or 96k/24bit?
24bit and 96kHz are entirely unnecessary for listening purposes. 24bit gives you the headroom (assuming suitable equipment) to exploit what your equipment can handle without unnecessarily risking quantisation noise or distortion. 96kHz when recording comes into play only when doing operations that may bleed into the audible region. Any pitch shifting (including autotune) can be affected here. Parametric equalisers implemented via IIR filters will have more natural behavior even in the audible high frequencies below 20kHz. Any kind of non-linear distortion is also prone to cause frequency bleeding where the results will be better when not just processing at a higher frequency but actually including (even if lower-quality) ultrasound components of the actual sound.
If your audio interface is capable of producing 96kHz (and with a quality better than a mere marketing gimmick), chances are that its analog circuitry is built for cutting off at higher frequencies, and that its own reduction in sampling frequency is designed for low latency rather than high quality. So even if you are doing all your processing at 48kHz, letting the hardware deliver at 96kHz might slightly improve the high frequency parts of the results.
That's audiophile talk, and you are doing a horror film. Unless you have extraordinary delicate film music, 48kHz editing should not really be a concern unless you have some specific audio effects that work better at 96kHz for whatever reason. The headroom of 24bit, however, should likely prove useful for most editing as well as recording tasks, assuming that your equipment does not deliver decidedly less than 16bit of resolution.
In particular since horror film audio tracks will likely feature a lot of dynamic compression, bringing up sounds like leaf rustling and heart beats to large volumes. Reducing only the final mix to 16bit (or whatever Youtube is going to work with) will improve your chances of getting a smooth result.