> I'm doing XSLT (2.0) Transformation XML 2 XML using saxon9. 
> Unmatched element name (input) should be retained in 
> Transformed/output XML file.
> Please suggest.

Use the identity template:

<xsl:template match="*">
  <xsl:copy>
    <xsl:copy-of select="@*"/>
    <xsl:apply-templates/>
  </xsl:copy>
</xsl:template>

Michael Kay
http://www.saxonica.com/