If you want to change the tomcat port number then you follow the following steps:-
Step1:- Go to tomcat => conf folder
Step2:- Edit server.xml
Step3:- Search "Connector port"
Step4:- Replace "8080" by your port number
Step5:- Restart tomcat server.
In server.xml Find:-
<Connector port="8080" protocol="HTTP/1.1" connectionTimeout="20000" redirectPort="8443" />
Change the port number to 9090:-
<Connector port="9090" protocol="HTTP/1.1" connectionTimeout="20000" redirectPort="8443" />