Are those two bikes your only two choices?
Do you really think you need disc brakes?
If you are planning to ride in the rain or through muck, then an 8-speed drivetrain may actually better in some ways because the muck is less likely to clog up the cogs while you are riding (you still need to clean everything after a messy ride) ... otherwise, 9-speed components (particularly, cassettes) are generally better than 8-speed components.
If you are riding in generally dry conditions, then disc brakes can probably be considered to be dead weight.
FWIW. Of the two bikes you mentioned, I would opt for the V-Brake version of the bike you prefer ... ride the bike for a month/season and then decide if you really want/need disc brakes BECAUSE you can retrofit disc brakes on the two bikes, but if you get the disc version, it appears that they won't have bosses to accept V-brakes.
If you feel you need disc brakes, you can begin with simply putting a disc brake on the front wheel (yes, you'll need a different hub).
FYI. Deore IS better than Alivio ... but, just as Deore is generally as functional as an LX/XT/XTR derailleur, Alivio is certainly as functional as the better components in the Shimano line-up ... most of the difference is in the weight & finish.
