1) Can i write this test with minimum of one month serious study.I would like to know the toughness of this exam.
It depends on your level of experience. I did the whole OCP for Oracle 7 in two weeks, including revision and sitting the exams, but I had years of experience. If you know what you are doing and you're a quick learner, it is possible.
2) And can i get free study material for 1z0-007 and practice tests.I would really appreciate this help.
The study guides cost money. The only way to get hold of them is to pay or to steal them. I don't recommend the latter.
3) Is it worth taking this oca 9i now??
As long as people are using Oracle 9i it's worth knowing how to use it, so the 9i certification is still worthwhile.
4) And do the certification really worth after they expire.
As with (3). While people use the product, the certification has some value.