What was the original term used for the club closest to what we now know as a 9 iron?

More interesting reading and links of interest

• While close to the 9 iron it is also, logically, similar to our modern day pitching wedge.
• The Historical Dictionary of Golfing Terms tells us the origin of the term is Scottish and likely a diminutive of nib = ‘nose’. Original niblicks were much shorter in the nose than other wooden clubs, hence ‘short-nose’ or ‘niblick’.
• According to a newspaper clipping from 1858 the niblick was most useful when the ball was in a cart-rut, horseshoe print or a round deep hollow. It seems golf was a little more difficult back in 1858!
• Apparently in 1858, while Musselburgh golfers used the term niblick, St. Andrews golfers called their version of the club a track-iron, likely a reference to cart tracks.
• If you want one you can buy one. The beautifully refurbished niblick in the image above is available for sale at St Andrews Golf Co 
• Wikipedia has a summary of olden day golf clubs if you'd like a quick read. And this is a great article at Thoughtco.com with some good images.