Had, and many people think so. Somebody even made a TrueType font called Dijkstra (http://ufonts.com/fonts/dijkstra.html)

If you want to keep one, it is worthwhile to download it from a few sites; multiple variants exist. AFAIK the only difference between them is the character set (a couple of fractions, IIRC)

In elementary school I was thought to draw in roundhand variant. The problem I had felt for years was that I could either draw fast or readable, but never both. So a number of years ago I set out to consciously change my writing style. I decided 2 requirements: letter shapes had to be as simple as possible, preferably a single stroke, but still distinguishable (eg. u, v, r can look similar in a rush). In the end I tried to distill as pure and simple a style I could and it turns out my letter forms are near identical to Dijkstra's. This makes me wonder whether he was taught this handwriting or went through the same thought process, knowing his inclinations I would not be surprised if he did.

What is remarkable is that on a computer, you can reedit what to write to death. On a piece of paper, you have to get it right the very first time.

I thought so, too.