Hi George,
in v8.2, all jar files from Tomcat and AwareIM was merge in Tomcat\lib but it has been split in v8.3.
1) When you want upgrade the tomcat, just replace all of the new Tomcat jar files into Tomcat\lib
2) the lib folder in root of AwareIM directory is for all native AwareIM jar files, but when you want upgrade your JDK, you have to copy the tools.jar into this directory, ignore the lib directory in WEB-INF (for me)
I have test upgrade the JDK to 1.8.0_181 with Tomcat 9.0.11 and didn't face any issue