Need to download iMovie '09 on MacBook Pro 16" with iMovie 10

I would like to transfer old Hi8 tapes onto my new MacBook using FireWire. I have an old Digital Sony Handycam and all of the required adapters to connect it to my MacBook USB-C ports. I tried importing a tape into iMovie 10 and while it did actually import the portion of the tape I played, the import screen on iMovie 10 had message "No Data Device Detected" the entire time and the audio could have been better. After doing some research it appears that maybe iMovie 10 is not 100% compatible with these old cameras but that iMovie '09 should still be. So, I would like to download iMovie '09 onto my MacBook in addition to iMovie '10 that I already have. In other words, I would like to have 2 different versions of iMovie on my MacBook so I can use the '09 version to import old Hi8 tapes and the '10 version for anything in the future. Is this possible? I did try to download '09 off the Apple site but after downloading it told me that I had downloaded an update and I already had the newer version so that bright idea didn't work. I am not a coder so if there is a way to do this without making changes in Terminal mode that would be my preference. TIA!