No, Hanuman isn't among the 11 Rudras. I discuss 11 Rudras and their significances in my answer here.
The 11 Rudras are:
They were Mrigavayadha, Sarpa, Niriti of great fame: Ajaikapat, Ahivradhna, and Pinaki, the oppressor of foes; Dahana and Iswara, and Kapali of great splendour; and Sthanu, and the illustrious Bharga. These are called the eleven Rudras. [Adi Parva, Sambhava Parva chapter 66]
Similarly in the Harivamsha Parva of Mahabharata:
सुरभी कश्यपात् रुद्रान् एकादश विनिर्ममे ।
महादेव प्रसादेन तपसा भाविता सती ॥१-३-४९
अजैकपाद् अहिर्बुध्न्यः त्वष्टा रुद्राः च भारत ।
त्वष्टुः चैव आत्मजः श्रीमान् विश्वरूपो महायशाः १-३-५०
हरः च बहु-रूपः च त्र्यम्बकः च अपराजितः ।
वृषा-कपिः च शम्भुः च कपर्दी रैवतः तथा ॥ १-३-५१
मृग-व्याधः च सर्पः च कपाली च विशांपते ।
एकादश एते कथिता रुद्राः त्रि-भुवन-ईश्वराः ॥१-३-५२
ब्शतं तु एवं समाख्यातं रुद्राणाम् अमित-औजसाम् ।
पुराणे भरतश्रेष्ठ यैः व्याप्ताः स चर-अचराः ॥१-३-५३
Hallowed by her own ascesis and by the grace of mahadeva, the daughter of daskha prajApati, and the wife of kashyapa prajApati, lady surabhi, moulded eleven rudrA-s. Apart from those eleven rudrA-s, Ajaika-pAd, Ahir-budhnya, TwaShTa, and ruda are also the progeny of surabhi, and tvaShTA's son is the highly glorious vishva-rUpa. Oh, king, the eleven rudrA-s are: Hara, Bahu-rUpa, Tryambaka, AparAjita, Vrishakapi, Shambhu, Kapardi, Raivata, MrigavyAdha, Sarpa, and KapAli. Oh, king, purANA-s tell that these eleven highly resplendent rudrA-s, on manifesting themselves manifoldly, are pervading the subtle bodies of all sessile and mobile beings, and thus they became the controllers of three worlds.
Thus Hanuman is not among the 11 Rudras. But what is the relation between Rudra and Hanuman? The relation is through the AshtaMurti form of Rudras. Hanuman is son of Vayu. And Vayu (Air) is one among the Eight form (AshtaMurti Roopam) of Shiva. I discuss it here.
सुवर्चला तथैवोमा सुकेशी चापरा शिवा।
स्वाहा दिशस्तथा दीक्षा रोहणी च यथाक्रमम् ॥८॥
सूर्यादीनां नरश्रेष्ठ रुद्राधैर्नामभिः सह।
पत्न्यः स्मृता महाभाग तदपत्यानि मे शृणु।
येषां सूतिप्रसूतैर्वा इदमापूरितं जगत् ॥ ९ ।।
शनैश्चरस्तथा शुक्रो लोहिताङ्गो मनोजवः।
स्कन्दः खर्गोऽथ सन्तानो बुधश्चानुक्रमात् सुताः॥ १०॥ (Vishnu Purana 1.8)
The wives of the Sun and the other manifestations, termed Rudra and the rest were respectively, Suvercalā, Uma, Vikesi, Sivā, Svāhā, Dišā, Diksā and Rohiņī. Now hear an account of their progeny, by whose successive generations this world has been peopled. Their sons, then, were severally, Sanaiśocara (Saturn), Sukra (Venus), the fiery bodied Mars, Manojava (Hanumān), Skanda, Swarga, Santana, and Budha (Mercury).
And in Markandeya Purana chapter 52:
The sun, the water, the earth, the fire, the ether, the initiated Brahman, and the moon, these became respectively their abodes. Suvarchala and similarly Uma, Vikeshi and another, Swadha, Swaha, and likewise Disha, Diksha, Rohini these respectively, O thou superior among the twice-born, became with the sun &c., the possession of the holders of the names commencing with Rudra &c.,. Their sons respectively were Shanaishchara, Shukra, Lohitanga, Monajava, Skandha, Sarga, Santana, and Budha.
Thus, in this way Hanuman is son of Shiva through his Ashtamurti form of Vãyu (Air). However in Shiva Purana there is a chapter called 'The incarnation of Hanuman', it is told Hanuman is also direct incarnation of Shiva. But in any case Hanuman isn't 11th Rudra.