You are seeing the correct behavior in the v9.9 :)-
Please refer this KB article resolution below and it is self explanatory:
Issue reported and Resolution:
Support for the application/xml MIME type was added in 9.10. Prior to 9.10, there was no ContentHandler for application/xml requests, so the Integration Server would place the incoming payload as an unparsed stream into the pipeline as a variable named contentStream. Starting in 9.10, application/xml content is handled just like text/xml content: the XML ContentHandler will put the content into the pipeline as node.
To use the old behavior, disassociate the application/xml MIME type from the XML ContentHandler by using the Java API. See the following method in com.wm.app.b2b.server.ServerAPI:
public static void removeContentHandler(java.lang.String content_type)
Deregisters a content type from the server. The default content handler will be associated with this content type.
content_type - A String specifying the MIME content type to deregistered.