You can bathe any age kitten - But only do it if it is really necessary as they should be cleaning themselves.
And beware the claws!! They will not appreciate having to have a bath and will kick, bite and claw to get away from the water (Note: This does not happen in all cats, but in most)
Sure you can, just be calm and patient... if you start them out early, they'll be used to it... Oliver gets a monthly bath cuz he sheds so much... make sure you use shampoo that is designated for kitties that young as well - if you can't find any, I would at least start getting him used to the bath without soap until he's a little older and you're able to use whatever shampoo you've bought.... as long as you're calm and use a soothing voice, your kitty shuld stay clam - if you're nervous, he will be too... look around on this site, people have different suggestions for cat bathing techniques... my ollie gets his in the human bathtub (but he is almost 4 and 14 pounds, haha)
he's really dirty he has spider webs all over him and dust. and i don't think he should be licking that stuff off and also he has poop hanging from his butt. is that a good reason to give him a bath?
Sounds fair enough to me! If you don't want to give him a full bath, you could try getting a reasonably damp towel and wiping that over him - A lot easier on him and you! But if he is really dirty, then give him a bath. Try to use kitten/small animal shampoo if you can and make sure you use warm water - But definately not hot! Test it on the back of your hand to make sure it is ok.