In [31]: df.Val = (df.Val.replace(r'[KM]+$', '', regex=True).astype(float) * \
   ....:           df.Val.str.extract(r'[\d\.]+([KM]+)', expand=False)
   ....:             .fillna(1)
   ....:             .replace(['K','M'], [10**3, 10**6]).astype(int))

In [32]: df
Out[32]:
         Date        Val
0  2016-09-23      100.0
1  2016-09-22  9600000.0
2  2016-09-21    54200.0
3  2016-09-20   115300.0
4  2016-09-19    18900.0
5  2016-09-16   176100.0
6  2016-09-15    31600.0
7  2016-09-14    10000.0
8  2016-09-13  3200000.0