SN9644 belongs to a German collector called Andre.
The picture below is just a generic yellow Computer Space image, I have not heard back from Andre yet regarding his machine. He posted a message on the Google discussion groups back in 2002 mentioning it would be a good idea if someone made a website listing the serial numbers of the surviving Computer Space machines alive today. Here is his post.
I tried emailing Andre to let him know I have started a site just like he mentioned, but his email address firstname.lastname@example.org seems to be inactive. If he ever sees this site, I hope he emails me.