Question 192853
This  is  an interesting  problem,  if  only  from  its  size.

we  started  by  arranging  the  factors  in  order.  

y=(x-9)(x-8)(x-2)(x-2)(x-3)(x-5)(x-8)

note  this  is  a  7th  degree function.  This  means(7  roots)  and  it  is  an  odd  function

we can  find  the  roots  from  the  factors,  for  example set  x-9=0,  x=-9  root  likewise  the  roots  in  order  are,  9,8,2,2,3,5,8.

Note  that  the  root  (2) happens  twice,  this  means  the  function  curve  just  touches  the  y=0  axis  but  does  not  pass  thru.  With  the  other  roots  the  function  intersects  and  passes  thru.

note  it  is  a  positive  function.  If  we  look  close  the  leading  coefficient  will  be  plus,  because  we  have  no  negative (x)  in  factors.  After  we  multiply  all  factors,  this  holds  true.

Summarizing,  it is  a  positive  odd  function,  with  7 roots,  and  these  roots  are  defined  by  the  factors. 

The  odd  positive  nature  indicates as  we  graph  the  function  starts at  the  left  with  a  negative  and  moves  upward  to  positive  right.  

If  we  use  a  standard  x - y  coordinate  system  and  make  just  a  rough  sketch, we  can  define  the  shape  of  the  function.

starting  at  lower  left  we  rise  thru x=(-8), turn and  pass  downward  thru  x=(-5) turn  and  pass  upward  thru  (x=-3),  turn  downward  and  just  touch  the  axis  at  x=(+2) before  turning  upward  and  then  downward  thru  x=(8),and  then  turn  and  pass upward  thru  x=(9)  and  continuing  upwards.  

We  see  6  turns  which  is  consistent  with  a  7  degree  function

We  would  probably  say  the  problem  is  complete  here,  but  you  seemed  to  want  to  expand  the  function.  This  is  a  lot  of  work  and many  chances  for  numerical  error.  

I  started  with  a  clean  sheet of  paper  sideways.

i  did  2  factor  by  themselves,  as  this  allowed  the  use  of  foil

1)(x+8)(x-8)=  x^2-64
2)(x-2)(x-2)=x^2-4x-4
3)(x+3)(x-7)=x^2 -4x-21
4)(x-5)   had  no  mate

now  we  multiplied 1*2  and  3*4

5)  x^4-4x^3-60x^2+256x-256
6)x^3-x^2-57x-135

and  lastly  we  multiplied  5*6
but  we  set  each  distribution  on  a  horizontal  line  and  matched  the  next  distribution  below.
This  resulted  in a  vertical  accounting  of  the  for  factors, one  vertical  column  for  each  degree.

The  result  was
y=x^7-5x^6-113x^5+409x^4+3960x^3+9303x^2-19968x+34560

my  graphing  calc  did  not  like  this  but  i  feel  the  above  sketch  is  correct.

to  recheck,  i  would  wait  a  day  and  redo