Is there a way to extend services if 52.217-8 Option to Extend Services was not included in the original contract?
Yes, but only bilaterally with what is called a bridge contract. The contracting officer cannot extend services unilaterally without the -8 clause. (Of course, the -9 provides unilateral authority but you didn't ask about that.) Note that bridge contracts are discouraged unless absolutely necessary and can come under strict scrutiny. They are also subject to the J&A requirements of FAR 6.302 or 13.5, as appropriate. You can read more about them at this informative link.