How possible would it be to obtain a waiver for OCS?

As a cyber officer, you wouldn't go to OCS, you would be a direct commission and go to the direct commission course. That's good news for you because you will have a better chance at a waiver going that route.

You need to speak with a cyber recruiter and lay it all on the table. If you decide to go NG, the state TAG would have to sign a memorandum for your waiver request which would then have to be approved by either USAREC or the cyber proponent (can't remember which). It's a tough road given that it is so recent and you were booted over the incident, but it can't hurt to talk to the recruiter.

I got an RE-3 when I got out of the active Army in 1989. They were passing them out like candy until the Gulf War kicked off a year later. I've met hundreds of people who got them. Apparently it was part of the Bush(41) Administration's plan to eliminate prior enlisted and thin the force after the Cold War ended. I didn't do anything wrong but I got the code anyway. I didn't know what it meant at the time but only found out how they screwed me when I tried to reenlist in 1992. They literally lied to my face when I signed my DD214 and told me that my "RE code will enable to me to reenlist anytime I want to." The Regular Army (RA) flat out rejected me in '92 and it took a year to get the waiver through the USAR. I switched from USAR to ARNG 3 years later without any problem. It could take a while but it's not impossible. That's the bad news.

The good news is that the Army is DESPERATE for Cyber officers. If you want active duty try them first. They might be willing to take you based upon your career field. You'll have to do an OCS enlistment which means you'll probably repeat Basic Training and then go to Ft Benning for the 14 week federal OCS course. Both will suck and if you do even a single day in OCS that is the only commissioning source you'll ever be allowed to go through. Something to keep in mind. Go to any additional schools (airborne, air assault, etc.) you can after BOLC because you may not ever get another chance.

If going RA fails go to BOTH the ARNG and USAR and get them competing with each other. ARNG now has an entire cyber brigade with many AGR positions. USAR is simply short of officers in general, especially field grades. The biggest downside to USAR is that you must accept a position anywhere in the US to get promoted whereas ARNG its only within your state. I knew I guy in the Captain's Career Course who lived in Austin and drilled in San Diego. He didn't mind but for some it is cost prohibitive. ARNG has state OCS programs that aren't any easier than active duty but they're accelerated course is shorter (8 weeks). The traditional course takes about 18 months (two week AT, 14 monthly drills, and a final two week AT) and has about a 70% drop-out rate.

One big hurdle that you'll have is getting the necessary TS-SCI clearance for cyber officers with a hot drug test on your record. That has been a hard No-Go at times the past but has been waivered depending on the needs of the Army (PFC Manning was an example of this). Your best bet is to be 100% honest with your recruiters because they'll find out everything anyway and it will go against you when they do.

Lastly, any subsequent DD214 will erase previous RE codes. Any deployment 180 days or longer with the ARNG or the USAR will generate a new DD214 with a new RE code. I'm working on my 5th one which I'll retire on. A new DD214 can be presented with an application to transfer to the RA and should smooth the process, though they'll still see your old DD214. Again, BE HONEST. When you do your security investigation look the investigator in the eye and tell the truth. Admitting mistakes is considered far better than hiding things. Your clearance is all about trust and if the investigator thinks you can't be trusted, you won't be.

The odds of you getting a morale waiver to attend OCS are slim to aliens invading earth