Cadd(b9)G means a quick progression from Cadd9 to G, with Cadd9 counting for only 1 beat.  
This occurs elsewhere in the chords with the same rule applying.

Intro: G5 C5 - G5 C5 G5 C5 
G5 G5 D5 - D5 C5 G5 
C5 G5 G5

Verse 1:
G5                   C5 - G5
Close your eyes and count to three
C5   G5   C5   G5   G5
I'm gonna make you proud of me
D5
Not today but that's alright
C5   G5   C5   G5 G5 
C5 - G5 C5 G5 C5 G5 
G5 - D5 - D5 C5 G5 C5 G5 G5
We have got a long long time

G5                       C5 - G5
I've got big plans and you do too
C5   G5   C5   G5   G5
And we've got ways to make them true
    D5
When I get old and if I do
C5   G5   C5   G5 G5 C5 - G5
I'm gonna get there next to you

           C5    C5
And you can count on me
           G5
And you can lean on me
          D5            D5  D5   C5
And we can throw our dreams to the wind
C5   G5   C5   G5 G5 
C5 - G5 C5 G5 C5 G5 
G5 - D5 - D5 C5 G5 C5 G5 G5
They'll find us again

G5              C5 - G5
With a hand to hold the rail
C5   G5   C5   G5   G5
Count the years that we've got left
D5
We've got the world by the tail
C5   G5   C5   G5 G5 C5 - G5
Oh we just don't know it yet

           C5    C5
But you can count on me
           G5
And you can lean on me
          D5            D5  D5   C5
And we can throw our dreams to the wind
           G5
And you can count on me
           C5
And you can lean on me
          D5            D5  D5   C5
And we can throw our dreams to the wind
C5   G5   C5   G5 G5  C5 - G5
They'll find us again
C5   G5   C5   G5 G5  C5 - G5
They'll find us again
C5   G5   C5   G5 G5  C5 - G5
They'll find us again