upgrade BB wont feel any different la.. dun simply say. ceramic/tiramic is expensive and that slight smoother bearing wont be felt unless u already have other good component to go with it at peak performance.

9 speed to 10 speed upgrade will definitely help on the climbing due to better gear ratio... 22t front with 36t rear.

weight does matter... 15kg vs 12kg big lot of different more over a 20kg bike. dun la simply give extreme different.
weight weenies actually refers to those who pay dearly to drop little weight different. its a misused term btw.

for newbie, 9 speed will do now.. ride more and build the stamina. upgrading to 10 speed help but most likely u will still push bike. might as while train harder and upgrade things like the wheelset to a lighter one that give you more significant differences during your ride. rolling weight can be felt more obvious that dead weight.