Older Shimano Ultegra Shifter compatibility

Any Shimano compatible 9 speed road shifter like the Sora you linked will work. While it will be visually different it will perform the same function. The last of these models were produced in 2007. While the Sora shifters you are looking at may be lower on the hierarchy list, they are likely equal to or better than your nearly the 20 year old technology you currently have. As new improvements are introduced Shimano eliminates the oldest technology and everything moves down a tier. Latest version of Ultegra is the previous version of Dura-Ace and it all moves down the line. My guess is you will be satisfied with a new Sora shifter.