This may be a matter of semantics as the FAR does not have a definition for “notice of intent”. We say "no it is not required" based on the following. 

What FAR 52.217-7 and FAR 52.217-9 have in common is “written notice”.

FAR 52.217-9(a) states “a preliminary written notice of its intent to extend at least…” followed by a fill-in. Whereas FAR 52.217-7 states “by written notice to the Contractor within…” followed by a fill-in.

FAR 17.207(a) states “When exercising an option, the contracting officer shall provide written notice to the contractor within the time period specified in the contract.” Bold italics added for emphasis.

Therefore, a preliminary notice of your intent to exercise a FAR 52.217-7 option is not required. The FAR is silent on what manner or medium you must use to provide the written notice. Because of the definition of “in writing” at FAR 2.101, you could use the SF 30 modification exercising the option as the “written notice” required by the clause itself and FAR 17.207(a). Again, bold italics added for emphasis.

Whatever you use as the written notice; it must be received by the contractor within whatever was used for your fill-in language in the FAR 52.217-7 clause (e.g # of days, ARO, end of the current contract term, etc.).