Is it within the officer's right to refuse to give me the other driver's insurance?
Yes. No law in Maryland requires that the officer provide you with that information. Indeed, the Maryland Public Information Act (which is Maryland's version of the federal Freedom of Information Act) expressly permits the police to deny requests for disclosure of investigative information.
Shouldn't the insurance company determine if the other party hit me or not?
Contact your insurance company and give it the relevant information. It can then determine if the other driver was responsible and if so attempt to recover from the other driver what your insurance paid you for your damages. That's what you have insurance for. If you do not carry comprehensive coverage that covers you for damages to your vehicle, then your other option is to sue the other driver for your damages. The other driver will then contact his insurance company, which will provide him with representation in the matter.
Seems like hes siding with the other gentleman saying he didnt hit me though I witnessed him hitting me and I know that damage was not there before that incident, and I have a video showing him initially drifting into my lane and my reaction to when he dropped back behind the camera and hit me.
No. The officer is merely telling you that he is not yet convinced that this person is the one who hit you and caused the damages. There is a difference. Before he may issue a citation here he must be convinced the other driver hit you since the state will have to prove that beyond a reasonable doubt at trial. His skepticism is not surprising since you are claiming that your car suffered “large damage” and yet the officer did not notice any damage from the other vehicle, and that would be unusual. Should you sue the other driver, you have the burden to prove he hit you, and you'd need to overcome that same skepticism from jurors: how is it that you suffered large damage in this collision but he suffered none at all?
In any event, the officer's determination will not decide the civil matter between you and the other driver. That is a matter for the insurance companies to work out or for a civil court to decide. All the officer does is decide whether to issue a citation to the other driver for any traffic offense committed.