DE 9 was extended north to US 13 Alt. (now US 13) in Wilmington by 1959, being rerouted off Smyrna-Leipsic Road to follow its current alignment to New Castle, passing through that city on 6th Street before continuing along its current alignment to Wilmington. At this point, the entire route was paved. The current Reedy Point Bridge carrying DE 9 over the Chesapeake and Delaware Canal was completed in 1968. By 1971, DE 9 was extended north to its current terminus at DE 2. DE 9 was realigned to bypass New Castle by 1984 by following Washington Street and DE 273. On October 27, 2008, construction began to convert the intersection at the southern terminus with DE 1 into an interchange, with Governor Ruth Ann Minner in attendance at the groundbreaking ceremony. Construction of the interchange at DE 1 was completed in 2009. By 2015, DE 273 was formally removed from the concurrency with DE 9 however , DE 273 signage remains along this segment.