What is wrong with him?

i have had my male winter white dwarf hamster for 2 weeks and one day. i know that is not a long time, but he should at least be used to me. I hold him quite often and i hand feed him a lot, so he gets used to my hand. i let him watch me feed him. He is only 9 weeks old. today i wanted to get him out and he ran into a corner and when i tried to get him, he hissed and bit my finger so hard it made it bleed. i disinfected it and washed the cut out, but i just don't understand. why does he run away when he knows i am not going to hurt him. i also have a male syrian and he is very sweet and loves me. so i have experience with hamsters. is there any way i can prevent being bitten again, or does he just need more time to get used to me?