I don't know beforehand, and will not speculate if you can get a version of Pages 13.2 - 14.1 after you upgrade to Ventura 13.7 — based on having Pages '09 installed on Mojave. Almost exclusively, my experience in the Pages community has been helping those who installed Pages v5 (Oct 2013) or later obtain the last compatible version for their later version of macOS when it was not directly available from the Mac App Store.
Pages '09 as a 32-bit application is inoperable after Mojave. Later versions of Pages are entirely different applications, both in functionality, and user experience because they were not based on the Pages '09 code. Their documents are not backward compatible with Pages '09. Some features may have been used in Pages '09 that the current Pages versions will not be able to convert, and this may prevent forward compatibility in rare cases.
If you upgrade to Ventura 13.7, you may or may not find yourself without a means to get the last compatible version of Pages for Ventura. Make backup copies of your existing Pages '09 documents. You may have to use the iCloud version of Pages on the copies to convert them to the current Pages document format. Let me know if you plan to upgrade to Ventura anyway, as there is a simple test in the Mac App Store to determine if you can get a last compatible version of Pages for Ventura.