ok grazie, sembra funzionare:
codice:
AlarmManager alarmManager = (AlarmManager) getApplicationContext().getSystemService(Context.ALARM_SERVICE);
Intent intent = new Intent(getApplicationContext(), AlarmReceiver.class);
PendingIntent alarmIntent = PendingIntent.getBroadcast(getApplicationContext(), 0, intent, 0);

Calendar date = Calendar.getInstance();
date.setTimeInMillis(System.currentTimeMillis());
date.set(Calendar.HOUR_OF_DAY, 9);
date.set(Calendar.MINUTE, 51);

try {
    alarmManager.setInexactRepeating(AlarmManager.RTC_WAKEUP, date.getTimeInMillis(), AlarmManager.INTERVAL_DAY, alarmIntent);
    alarmManager.set(AlarmManager.ELAPSED_REALTIME_WAKEUP, SystemClock.elapsedRealtime() + 60 * 1000, alarmIntent);
} catch (NullPointerException ex) {
    Log.e("NULLP", ex.getMessage());
}
aggiungendo tutto il resto.
faccio un pò di test più approfonditi!