If I remember correctly the patched content is always included in the subsequent main release. However as 3.9 is likely several months away, what is the problem with patching 3.8? After all, the patches are not all new content, they typically mainly include corrections to existing issues.
e.g. (3.82 patch)
- various Weapons.properties fixes
- static.ini fixes and updates
- Skua wing fold fix (western)
- Seafire Mk II spawn fix (western)
- DH Hornet collision and spawn bug fix (western)
- Junkers G38 engine and take off fix (western)
- B-52, B-47, C-135 families FMB crash fix (Storebror)
- F-84 RATO fix (Storebror)
- ag_China_Coast airfield fixes (Bombsaway)
- Iwo Jima airfield fixes (Bombsaway)
- B-29 Alley Iwo Jima fixes (Bombsaway
- Falklands/Malvinas update (Bombsaway)
- RAF cockpits - no more pin-ups (Airbourne)