|Thanks for your comments guys. The 9 lights are actually bokeh highlights from the windows in the background.
I used some black card to cut out a number 9 shape (about 1cm high), and glued the "hole" in the nine with a bit of cotton, which you can see. so then I used an elastic band to secure the entire black card with the 9 hole in it on the lens. Any bokeh highlights then took on the shape of the 9. Interestingly, when I stepped down to f22 the entire image took on a 9 shape. Basically, you can get some cool effects with hearts, stars, 4-leaf clovers, etc The vignette look is simply because the shot was taken at night so the building in the background was surrounded by darkness.
Hope that helps :)