Both both the sections have the common title "Implicit Objects"
One main difference is:
Implicit Objects :
These are available implicitly (without any need to prior declaration) in the scriptlets and scriptlet expressions. There are total 9 objects (request, response, pageContext, session, application, out, config, page, exception).
These Object names with prefixes jsp, _jsp, jspx and _jspx, in any combination of upper and lower case, are reserved by the JSP specification.
Implicit Variables :
These are available implicit in EL Expressions. They are pageContext, pageScope, requestScope, sessionScope, applicationScope, param, paramValues, header, headerValues, cookie, initParam