critical path and IC delay

Yes, but there are a ton of things that can cause the problem(it's seldom black-and-white). Using memories causes the routing congestion to go up, just like using any resource. One thing to look at in the fit report is routing utilization(average and peak). There's no perfect rule of thumb, but it would be worth posting. (If your path is using direct routes, then it's not a routing issue anyway).

If M9Ks are being used to build larger rams, then it can be a problem too. For example, if it was building an 18Kx72 RAM, for example, then your address bits would be fanning out to 144 M9Ks, and are naturally going to have long hops(unless logic is duplicated, either in the code, with directives or physical synthesis).