Hello Sriraman,
No, it is not possible; the SPA8800 gateway is not supported on the ISR 2901 with Call Manager Express. The SPA 8800 was only supported with Business Edition 3000, which is End of Sale. On the following link you can confirm this, tables 2 and 3.
http://www.cisco.com/c/en/us/products/collateral/unified-communications/business-edition-3000/data_sheet_c78-718398.html
On the following link you will find the supported firmware, platforms, memory, and voice products on Call Manager Express.
http://www.cisco.com/c/en/us/td/docs/voice_ip_comm/cucme/requirements/guide/cme95spc.html
Best Regards,
Cristina Alvarado
Global Virtual Engineering - Partner Help.