I am a security guard (non commission) in Texas, just started yesterday. The shifts after training will be alone for up to 12 hours and at night. I have the basic rights of citizen arrest, so can I carry handcuffs? If I had to wait for police to arrive I’d feel better having the person cuffed instead of hoping he doesn’t try to attack me, which comes to my next question. Could I carry OC Spray? In the event I did get attacked? Or would all of this be up to the security company?

You are looking at a huge liability issue. Check with your company about their policies. They carry a bond on you and there are specific terms under which you can operate. Your primary duties are to Observe and report, you are not a police officer and you represent your company and they will be ultimately held responsable for you actions. At the least, you’ll get fired, at the worst, you go to jail.
In NJ you must be 18 to carry cuffs and not have a criminal record. OC spray is allowed in small quantity, not sure of the cut off, but its not the size police use.
Personally, I’d carry a gun. You ARE in Texas. I believe they have no open-carry laws if my memory serves. Strap on a side arm, son. You is in DANGER.