No, a connection cannot be made to a HADR standby database. IBM says that it understands that customers would like select-only access to the HADR standby database, and that it might be available in some future release of DB2.
However, when you have a physical server that only contains one or more HADR standby databases (except for occassional takeovers that are necessary for high availability and/or maintenance) you only need to have 100 PVU (processor value units) worth of DB2 licenses on the standby server, regardless of the number of actual CPU's or cores on the server. 100 PVUs is equivlient to 1 dual-core Intel CPU. If read access is allowed, that is likely to change.
M. A. Feldman
IBM Certified DBA on DB2 for Linux, UNIX, and Windows
IBM Certified DBA on DB2 for z/OS and OS/390