SQL Server 2008 R2 High CPU
I would recommend starting with a methodology like Waits and Queues. But at 10k queries per second you should expect some CPU to burn. Whether it's more than it should be is really hard to tell just from the info you gave. The methodology linked will at least help you find bottlenecks. 

The biggest bang for the buck would probably be... not to send 10k queries a second. Cache in the client. Look at How StackOverflow Scales with SQL Server and see how SE caches as much as possible in the web tier layer before hitting the server.

Just in case, do a couple of DBCC SQLPERF ('SPINLOCKSTATS') and see if anything stands out.