Hate to break the news to you, but the only thing you will be grappling with a +36 modifier at CR 10th is a Rakshasa, the Guardian Naga, maybe an Adult White Dragon (before Str), the Juvenile Silver, a Noble Salamander, possibly a Juvenile Red (but only if you roll well/debuff him), an 11-headed Pryohydra (which can still kill you), a Clay Golem (but it's immune to magic anyway), a fire Giant, a Formian Myrmarch (but it just teleports), possibly a Belbilith (but it plane shifts), a Couatl (plane shift again), and maybe a Young Adult Brass.
About half of the CR 10s alone are able to escape. Some of them can beat your grapple check by taking 10.
In other words, not likely useful, and very situational. A Druid would do better just Wild Shaping than putting that much effort into using Kelpstrand.
I gotta say, I don't know what you are talking about.
a +36 grapple check is HUGE at level 10. I just went through the Monster Manual 3. out of the 130ish creatures there, there were only 15 who could regularly beat all 6 +36 grapple checks. There CL's are: 11,14,15,15,15,16,17,17,17,17,18,18,19,20,20.
Every other corperal creature (all 115 of them) would get it's ass kicked by a single 160gp arrow!
And at later levels I was going to use a Kensai's imbue ability to pump the druids BAB by 8. By then, the druid has a higher CL, BAB and wisdom so the grapple checks will
beat every creature in the book!! So, is there any rule that limits CL and DC to the min, or can I own almost everything with this totaly legal and DEVESTATING tactic?