is XBee-PRO 900 compatible with XBee-PRO 900HP (S3B) 10K?
Are in general Xbee modules compatible between families? I tried to change firmware but it didn't help.
Unfortunately they are not compatible with each other if they have different firmware. The XBP9B-DP 10K is going to speak a different over the air language than the XBP09-DP.
However, I have had success loading matching firmware into two different Xbees. In my case, the XBPB9B-XCWT and XBP9B-DMWT both loaded as XBP9B-DMWT. You may have to use the recovery procedure of the XCTU software to do this. Click the wrench icon (tools) and select 'Xbee recovery' from the drop down.