Post ACL you should be seeing a physio? are you? they should be able to answer that question for you.
healing times vary for everyone... for your knee to feel 100% it's usually 6 - 12 months after op depending on the demand you are placing on the knee - e.g. if your trying to ski or something it may take longer to feel good.
Your knee feeling tight with bending and the strange pains are generally pretty normal at 9 weeks - depending on exactly how strange your pains are.
As for the swelling - it all depends on the demand you put on your knee and what your goals are... As you continue to do more and more things which put more demand on the knee that causes the swelling to stick around a little longer.
You should be seeing a physio if you arent already.