Narita to Haneda later in evening

We are scheduled to arrive Narita at 9pm and depart from Haneda early the next morning. We've reserved a hotel room at Haneda, but now see that the last bus from Narita to Haneda departs at around 9:30. We won't make that, I am sure. So what are our options to get to Haneda -- other than a very, very expensive cab? Help much appreciated.

Relax.
You don't need to take cab.

You can arrive Haneda airport in the arrival date by taking trains.

If you ha ve enough money, express is also available.

If any question, don't hesitate contact with me.

You can use this HP

http://www.jorudan.co.jp/english/

Move to Tokyo Station by either Tokyo Shuttle(900 or 1500 Yen at night) or The Access Narita(1000 Yen).
http://accessnarita.jp/en/home/
http://www.keiseibus.co.jp/global/en/nrt00.html

Walk to Tokyo Station from the bus stop(5-8 mins), then move to Shinagawa Station(by Yamanote or Keihin-Tohoku line), leave the gate at Shinagawa, then go to Keikyu Shinagawa Station(walking distance), then go to Haneda Airport Station. This route costs you 572 Yen per person(excluded above bus fair).

or

Go to Tokyo Station. Then go to Hamamatsu-cho Station by either Yamanote or Keihin-Tohoku line. Leave the gate at Hamamatsu-cho Station, switch to Tokyo Mono Rail, then go to Haneda Airport Station. This route costs you 637 Yen per person(excluded above bus fair).

tokyo friend 48: Move to Tokyo Station by either Tokyo Shuttle or The Access Narita

You had better catch a Tokyo Shuttle bus, an Access Narita bus or a limousine bus
scheduled to depart from NRT Terminal 2 by 22:05 and from NRT Terminal 1 by 22:10
in order to take trains to a station inside or near Haneda Airport soon after reaching Tokyo Station Yaesu Entrance bus terminal.

Catching Keisei Skyliner 56 scheduled to depart around 22:30, you can take it to Nippori Station, pass through a transfer gate to JR, catch a Local train departing at Track 9 or 10 and switch to either Tokyo Monorail in Hamamatsucho or to Keikyu in Shinagawa.
In this case, you should reserve seats and buy tickets of the Keisei Skyliner at a Keisei counter in your NRT terminal.

For more detailed answers, you had better clarify the following points.
: How many travelers will be in your group?
(That may affect a taxi fare, which is paid per car. Usually one taxi car can carry 4 passengers.)
: Will the travelers include someone before reaching 12 years old? If so, how old will he/she be?
(That may affect whether you should secure a seat for him/her.)
: Will you stay inside or outside Haneda Airport?
(That may affect your route.)
: Will you travel from Narita Airport on a weekday?
(That may affect railroad timetables. Public holidays until the coming September will be July 21, September 15 and September 23.)