We recently went live with HCM 9.2 (8.55.14) & FSCM 9.2 (8.55.14) from 9.1 (PT 8.54) version.
HCM for example:
Hop1 - Per oracle recommendation, we did a major patching upgrade (Mp9, Bundles 14 thru 21) + People tools 8.55.06 upgrade
Hop2 - then we upgraded out Application version to 9.2 (HCM & FSCM) plus PT upgraded to 8.55.14
1) I think you can Hop1 and then do Hop 2 option, this will be a two separate projects and time consuming. One advantage of this method is you can catch up with your customizations as 9.2 application version is completely different with all the fluid changes.
2) If you decide to choose Hop 2 option directly then, as far as the application version this will be a huge change, brining the customizations will be bit challenging, thorough Fit-Gap & Keep Drop needs to be done.
Depending upon your project timeline and available budget, etc., you can decide and choose the best method which works for your organization.
Also, In your case, for 8.8 application version I think Oracle might have already stopped the support. please refer oracle documentations to find the certified upgrade path and proceed accordingly.
Let me know if you have any questions. Thanks