Board Thread:General Discussion/@comment-4963061-20190519055201/@comment-28802873-20190519083143

If he was, he would've been there way before the Omnitrix landed, since he and Max are old buddies. Not to mention that instead of working directly on the watch, he stayed behind to examine what was messing with it.

Granted, he could just be observing Ben from afar, but that theory's not very solid.

Besides, given how he doesn't react much to Ben's antics, even if he knew about alien life, he probably isn't too involved with the Omnitrix. Probably heard of it back when he was a Plumber (if those do exist), but it's obvious that while he seems to know a lot, he doesn't know everything about it, how to open it or to fix it immediately.