Also apart from bios spinning up the disks, it's highly likely the OS will also access all disks as part of start up.
Why do you want to stop the disk spinning up until needed? I can't think of a single use case that would warrant a reason to do so.
Power consumption is almost non-existent, and if that was a true concern then you wouldn't be powering a PC.
Drive wear is also not a concern as the disks are designed to do this.