python date code?

The 9 and the 96 are the date code. I have no idea which remote works with that revision of the alarm.

it depends if you have the external antenna mounted on your windshield. Being that its an "hf" it most likely should. But if its missing, that may be another thing you'll have to buy. Or does it have a lil black thin wire just hanging off the brain? probably about a 20guage wire about 16 inches long. I t may be one of the older ones being that it went off when you replaced your battery. In the mid 90's DIE changed their alarm so that even disconnecting the battery the alarm would retain its last state(armed or disarmed)so it wouldnt go off when replacing a battery.(unless of course the alarm was armed before you disconnected the battery. Can you get any picture of it? I may be able to tell by looking at the main harness. Really old ones had like a translucent white colored harness. The color of the plastic looked like the plastic they make milk jugs out of. With age it would look brownish or yellowish. Then they changed them to a solid white harness sometime in the 90's. If 9-96 is your date code, that coincides with around the time DEI was changing a lot of their alarms. So even if you do get the right part number remote(475t for example) it still may not work depending on the age of your unit. Older ones had a red led on the remote. Then they switched to green led's on the remotes when they chaged up their alarms. But they kept a lot of the same part numbers. But I'm pretty sure I can tell by the wire harness if you need a red led or green led remote.

It has a translucent white harness. If I remember right it was armed when I first connected the battery back up. There is a black wire a little thicker than the rest thats comming out of the main box that might be the antenna. Its the only wire that you cant disconnect from a harness and i cant follow it to see what it is.

That thick black cable that you can't disconnect is the coaxial antenna cable, going up to the antenna on the windshield.

DEI made older remotes that have a red LED that lights up when you press the buttons, and then sometime in the late 90s they changed to a green LED.

Someone told me that all red-LED remotes are compatible with each other, and that all green-LED remotes are compatible with each other...........that is, if your system is supposed to have a red remote, you could buy whatever kind of red remote you could find, it might just look different from the original. But I'm not sure myself.

Here's the way I look at it:

You could take a gamble and buy a used remote on eBay for maybe $20-30 and try to program it yourself, but there's half a chance you'll get the wrong one.

You could bring the car to a DEI dealer, who would probably charge you something like $70 for the remote, but if they can't get it to program to the car, they shouldn't charge you for it.

In your case, it might be a better bet just to get it locally at full price, because you'll be sure to get one that works.

The alarm you are describing needs a red led remote. It originally came with a 4 button red led remote. I think I may actually have a 2 button red led remote lying around. If I do, I'll give it to you for next to nothing if you want it. The problem is, DEI doesn't make the red led remotes anymore. So to find one, you'll have to luck out and find a dealer that still has one, or look on ebay. And like Chris said, whose to say if the remote will even work? I honestly have no way to tell you whether mine works or not(other than the LED lights up).

Ok, I do have a two button red LED remote. Its a DEI491. You can have it for 10 bucks if you want it. But then again, I have no old alarm to test it on to see if it actually work. All I know is the LED lights up when you press the buttons.

Sorry for the delay I just got back off a trip.
Long before I started researching this online I went to the 2 dealers I could find in this area and they weren't willing to help. I would love help from a dealer but looks like I don't have that option. I got a response back from a site and wondering what you guys think about it.

https://www.drdetailshop.com/485M.htm

I found it on other sites for $30

Also would using the 2 button remote limit some of the options the system has?

No the two button wont lose any funtions as compared to the 4 button remote. On the 4 button remote, the two top buttons (I and II) are arm, and disarm, the bottom two buttons (III and IV) are for panic and your channel 2 output (usually trunk pop)To trigger channel 2 you have to press button III for 3 seconds. Hold down buttons I and II at the same time for 3 seconds and that will trigger channel III (usually remote start). You will still have all these functions with a two button remote, except the configuration will be different, you wont have a dedicated button for arm and disarm or panic. On a two button remote, button one is for arm/disarm and panic. Press it to arm the system, and press the same button to disarm the system. Press and hold button 1 for 3 seconds and that will trigger panic mode. Button two is for channel 2 (trunk pop). Press and hold button 2 for 3 seconds to trigger channel 2. Channel three is the sameas on the 4 button remote, press and hold buttons one and two for 3 seconds.   
I saw that remote on the link you posted, that remote should work on your system. Here is the link to the remote that I have.
https://www.drdetailshop.com/491T.htm

Cool. Ill take that remote off your hands then. I will PM you my email address.