Your timings are tight. It will likely take at least a half hour to deplane and another half hour to clear customs. It will take anywhere from 15 minutes to 45 minutes depending on Metro or Cercanius transportation to Chamartin. That doesn't leave much slush (I make 20 minutes) for any delays. I'd have a plan 'B'.
The last Cercanius that gets you to Chamartin in time leaves T4 at 0958. The last viable metro would leave either T1T2T3 or T4 not later than 0945.
Trains from Madrid to Ponferrada depart from Chamartin station.
You can buy tickets at the Renfe Cercanius office at airport T4. If you arrive at T1T2T3 ... you'd best proceed to Chamartin.
2007
Madrid Airport to train station Chamartin
a. Chamartin is reached by Metro. Take line 8 from airport T1-T2-T3 or T4 to Nuevos Ministerios; and, line 10 to Chamartin. Trains run 6 - 12 minutes. Allow 40 minutes.
b. Chamartin is reached by Renfe Cercanius direct from Madrid Airport T4. Trains run every half hour. Allow 12 minutes travel time.
Madrid Metro
http://www.metromadrid.es/en/index.html
Madrid Metro Map
http://www.metromadrid.es/export/sites/metro/comun/documentos/planos/Planomayo2013.pdf
Madrid Cercanius (operated by Renfe)
http://www.renfe.com/viajeros/cercanias/madrid/index.html