Yes it does but... the spin down timer on this drive is stupid. Yes you can send a spin down timer set to it, but once it wakes up, this setting is gone and one needs to re-send the set command again. HDs used to be easier to work with than this.
that really depends on what you are using the drive for. if it's your main HDD (with an OS installed on it), the hard drive will likely see little to no "idle time". idle time generally refers to CPU inactivity, the HDD will never stop spinning completely. modern hard disks do, however, vary their spindle speed based upon current workloads and "rev" up and down to save power consumption. in the most general sense, the answer to the first part your question is YES.